├── .gitignore
├── 2 Dimensional Arrays
    ├── ArrayOfString.c
    ├── MatrixAddition.cpp
    ├── MatrixMultiplication.cpp
    ├── SumOfColumn.cpp
    ├── SumOfRows.cpp
    └── SumOfallElements.cpp
├── Arrays
    └── Arrays.cpp
├── Binary Trees
    ├── BFSTraversal.cpp
    ├── BinaryTrees.cpp
    ├── InorderTraversal.cpp
    ├── PostOrderTraversal.cpp
    └── PreOrderTraversal.cpp
├── CONTRIBUTING.md
├── LICENSE
├── Linked List
    ├── Code1.png
    ├── Code2.png
    ├── Code3.png
    ├── Code4.png
    ├── Code5.png
    ├── DoubleLinkedList.html
    ├── DoublyLinkedList.cpp
    ├── LinkedList.cpp
    ├── LinkedList_Array.cpp
    ├── compare.png
    └── dll.png
├── Queue
    ├── CircularQueueArray.cpp
    ├── Circular_Queue_LinkedList.cpp
    ├── Queue_Array.cpp
    └── Queue_LinkedList.cpp
├── README.md
└── Stack
    ├── Stack_Arrays.cpp
    └── Stack_LinkedList.cpp


/.gitignore:
--------------------------------------------------------------------------------
1 | *.exe
2 | 


--------------------------------------------------------------------------------
/2 Dimensional Arrays/ArrayOfString.c:
--------------------------------------------------------------------------------
 1 | #include<stdio.h>
 2 | int main()
 3 | {
 4 | 	int n,size,i;
 5 | 	printf("Array of Strings code!\n");
 6 | 	printf("Enter the size of the array you want: ");
 7 | 	scanf("%d",&n);
 8 | 	printf("Enter maximum String size: ");
 9 | 	scanf("%d",&size);
10 | 	char str[n][size];
11 | 	for(i=0;i<n;i++)
12 | 	{
13 | 		printf("Enter the %d element of the array: ",i+1);
14 | 		scanf("%s",&str[i]);
15 | 	}
16 | 	for(i=0;i<n;i++)
17 | 	{
18 | 		printf("The %d element of the Array of String is: %s\n",i+1,str[i]);
19 | 	}
20 | }
21 | 


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/2 Dimensional Arrays/MatrixAddition.cpp:
--------------------------------------------------------------------------------
 1 | #include<iostream>
 2 | using namespace std;
 3 | int main()
 4 | {
 5 | 	int r1,r2,c1,c2,r,c;
 6 | 	printf("Addition of Two Matrix!!!\n\n");
 7 | 	printf("Enter the size of the first matrix\n");
 8 | 	printf("Number of rows: ");
 9 | 	scanf("%d",&r1);
10 | 	printf("Number of columns: ");
11 | 	scanf("%d",&c1);
12 | 	printf("\n");
13 | 	printf("Enter the size of the second matrix\n");
14 | 	printf("Number of rows: ");
15 | 	scanf("%d",&r2);
16 | 	printf("Number of columns: ");
17 | 	scanf("%d",&c2);
18 | 	printf("\n");
19 | 	if((r1==r2)&&(c1==c2))
20 | 	{
21 | 		cout<<"Matrices are of same size and are compatible to be added!!"<<endl;
22 | 		int m1[r1][c1],m2[r2][c2],m3[r1][c1];
23 | 		printf("Enter the first matrix values row wise!!\n");
24 | 		for(r=0;r<r1;r++)
25 | 		{
26 | 			for(c=0;c<c1;c++)
27 | 			{
28 | 				scanf("%d",&m1[r][c]);
29 | 			}
30 | 		}
31 | 		cout<<"Enter the second matrix values row wise"<<endl;
32 | 		for(r=0;r<r1;r++)
33 | 		{
34 | 			for(c=0;c<c2;c++)
35 | 			{
36 | 				cin>>m2[r][c];
37 | 			}
38 | 		}
39 | 		for(r=0;r<r1;r++)
40 | 		{
41 | 			for(c=0;c<c1;c++)
42 | 			{
43 | 				m3[r][c]=m1[r][c]+m2[r][c];
44 | 			}
45 | 		}
46 | 		cout<<"\n\nDisplaying the final matrix after addition\n";
47 | 		for(r=0;r<r1;r++)
48 | 		{
49 | 			for(c=0;c<c1;c++)
50 | 			{
51 | 				cout<<m3[r][c]<<"\t";
52 | 			}
53 | 			cout<<"\n";
54 | 		}
55 | 	}
56 | 	else
57 | 	{
58 | 		cout<<"Matrices are of different size and thus matrix addition is not applicable!!"<<endl;
59 | 	}
60 | }
61 | 


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/2 Dimensional Arrays/MatrixMultiplication.cpp:
--------------------------------------------------------------------------------
  1 | #include<iostream>
  2 | using namespace std;
  3 | int main()
  4 | {
  5 | 	int r1,c1,i,j,r2,c2,flag,k;
  6 | 	cout<<"Matrix Multiplication (Naive Method)"<<endl;
  7 | 	cout<<"Enter the matrix 1 details"<<endl;
  8 | 	cout<<"Number of Rows: ";
  9 | 	cin>>r1;
 10 | 	cout<<"Number of columns: ";
 11 | 	cin>>c1;
 12 | 	cout<<"Enter the matrix 2 details"<<endl;
 13 | 	cout<<"Number of rows: ";
 14 | 	cin>>r2;
 15 | 	cout<<"Number of columns: ";
 16 | 	cin>>c2;
 17 | 	if((r1==c2)&&(c1==r2))
 18 | 	{
 19 | 		cout<<"Matrix 1 * Matrix 2 and Matrix 2 * Matrix 1 both possible!!\nPlease note that both are not same thing!!"<<endl;
 20 | 		cout<<"Press 1 for Matrix 1 * Matrix 2"<<endl;
 21 | 		cout<<"Press 2 for Matrix 2 * Matrix 1"<<endl;
 22 | 		cout<<"I must warn you! If you press anything except 1 and 2 I will exit the code :)\n";
 23 | 		cin>>flag;
 24 | 	}
 25 | 	else if(c2==r1)
 26 | 	{
 27 | 		cout<<"Matrix 2 * Matrix 1 is possible"<<endl;
 28 | 		flag=2;
 29 | 	}
 30 | 	else if(c1==r2)
 31 | 	{
 32 | 		cout<<"Matrix 1 * Matrix 2 is possible"<<endl;
 33 | 		flag=1;
 34 | 	}
 35 | 	else
 36 | 	{
 37 | 		cout<<"Matrices are incompatible to be multiplied"<<endl;
 38 | 		flag=0;
 39 | 	}
 40 | 	if(flag==0)
 41 | 	{
 42 | 		cout<<"Sorry but I must exit the code now!!\nBut hey! Before I leave I have a tip:\nFor Matrix Multiplication row of one matrix must be equal to column of other matrix in size";
 43 | 	}
 44 | 	else if((flag==1)||(flag==2))
 45 | 	{
 46 | 		int mat1[r1][c1],mat2[r2][c2];
 47 | 		printf("\nOkays! So let's multiply the matrices now\n");
 48 | 		printf("\n\nEnter %d values row wise for the first matrix\n",r1*c1);
 49 | 		for(i=0;i<r1;i++)
 50 | 		{
 51 | 			for(j=0;j<c1;j++)
 52 | 			{
 53 | 				cin>>mat1[i][j];
 54 | 			}
 55 | 		}
 56 | 		printf("\n\nEnter %d values row wise for the second matrix\n",r2*c2);
 57 | 		for(i=0;i<r2;i++)
 58 | 		{
 59 | 			for(j=0;j<c2;j++)
 60 | 			{
 61 | 				cin>>mat2[i][j];
 62 | 			}
 63 | 		}
 64 | 		if(flag==1)
 65 | 		{
 66 | 			cout<<"\nMatrix 1 * Matrix 2\n\n";
 67 | 			int mat[r1][c2];
 68 | 			for(i=0;i<r1;i++)
 69 | 			{
 70 | 				for(j=0;j<c2;j++)
 71 | 				{
 72 | 					mat[i][j]=0;
 73 | 					for(k=0;k<r2;k++)
 74 | 					{
 75 | 						mat[i][j]+=mat1[i][k]+mat2[k][j];
 76 | 					}
 77 | 				}
 78 | 			}
 79 | 			cout<<"Displaying the final matrix"<<endl;
 80 | 			for(i=0;i<r1;i++)
 81 | 			{
 82 | 				for(j=0;j<c2;j++)
 83 | 				{
 84 | 					cout<<mat[i][j]<<"\t";
 85 | 				}
 86 | 				cout<<"\n";
 87 | 			}
 88 | 		}
 89 | 		else if(flag==2)
 90 | 		{
 91 | 			cout<<"\nMatrix 2 * Matrix 1\n\n";
 92 | 			int mat[r2][c1];
 93 | 			for(i=0;i<r2;i++)
 94 | 			{
 95 | 				for(j=0;j<c1;j++)
 96 | 				{
 97 | 					mat[i][j]=0;
 98 | 					for(k=0;k<r1;k++)
 99 | 					{
100 | 						mat[i][j]+=mat2[i][k]+mat1[k][j];
101 | 					}
102 | 				}
103 | 			}
104 | 			cout<<"Displaying the final matrix"<<endl;
105 | 			for(i=0;i<r2;i++)
106 | 			{
107 | 				for(j=0;j<c1;j++)
108 | 				{
109 | 					cout<<mat[i][j]<<"\t";
110 | 				}
111 | 				cout<<"\n";
112 | 			}
113 | 		}
114 | 	}
115 | 	else
116 | 	{
117 | 		cout<<"I did warn you!! You chose wrong! Good bye:)\n";
118 | 	}
119 | }
120 | 


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/2 Dimensional Arrays/SumOfColumn.cpp:
--------------------------------------------------------------------------------
 1 | #include<iostream>
 2 | using namespace std;
 3 | int main()
 4 | {
 5 | 	int r,c,i,j,sum;
 6 | 	cout<<"Code to find the sum of each column of the matrix\n\n";
 7 | 	cout<<"Number of rows: ";
 8 | 	cin>>r;
 9 | 	cout<<"Number of columns: ";
10 | 	cin>>c;
11 | 	int mat[r][c];
12 | 	printf("Enter %d values for matrix to be filled row wise from top\n",r*c);
13 | 	for(i=0;i<r;i++)
14 | 	{
15 | 		for(j=0;j<c;j++)
16 | 		{
17 | 			cin>>mat[i][j];
18 | 		}
19 | 	}
20 | 	for(i=0;i<c;i++)
21 | 	{
22 | 		sum=0;
23 | 		for(j=0;j<r;j++)
24 | 		{
25 | 			sum+=mat[j][i]; //index according to the for loop!
26 | 		}
27 | 		printf("Sum of the %d column of the matrix = %d\n",i+1,sum);
28 | 	}
29 | }
30 | 


--------------------------------------------------------------------------------
/2 Dimensional Arrays/SumOfRows.cpp:
--------------------------------------------------------------------------------
 1 | #include<iostream>
 2 | using namespace std;
 3 | int main()
 4 | {
 5 | 	int r,c,i,j,sum;
 6 | 	cout<<"Code to find the sum of each row of the matrix\n\n";
 7 | 	cout<<"Number of rows: ";
 8 | 	cin>>r;
 9 | 	cout<<"Number of columns: ";
10 | 	cin>>c;
11 | 	int mat[r][c];
12 | 	printf("Enter %d values for matrix to be filled row wise from top\n",r*c);
13 | 	for(i=0;i<r;i++)
14 | 	{
15 | 		for(j=0;j<c;j++)
16 | 		{
17 | 			cin>>mat[i][j];
18 | 		}
19 | 	}
20 | 	for(i=0;i<r;i++)
21 | 	{
22 | 		sum=0;
23 | 		for(j=0;j<c;j++)
24 | 		{
25 | 			sum+=mat[i][j];
26 | 		}
27 | 		printf("Sum of the %d row of the matrix = %d\n",i+1,sum);
28 | 	}
29 | }
30 | 


--------------------------------------------------------------------------------
/2 Dimensional Arrays/SumOfallElements.cpp:
--------------------------------------------------------------------------------
 1 | #include<iostream>
 2 | using namespace std;
 3 | int main()
 4 | {
 5 | 	int r,c,i,j,sum;
 6 | 	cout<<"Code to find the sum of all elements of the matrix\n\n";
 7 | 	cout<<"Number of rows: ";
 8 | 	cin>>r;
 9 | 	cout<<"Number of columns: ";
10 | 	cin>>c;
11 | 	int mat[r][c];
12 | 	printf("Enter %d values for matrix to be filled row wise from top\n",r*c);
13 | 	for(i=0;i<r;i++)
14 | 	{
15 | 		for(j=0;j<c;j++)
16 | 		{
17 | 			cin>>mat[i][j];
18 | 		}
19 | 	}
20 | 	sum=0;
21 | 	for(i=0;i<r;i++)
22 | 	{
23 | 		for(j=0;j<c;j++)
24 | 		{
25 | 			sum+=mat[i][j]; //index according to the for loop!
26 | 		}
27 | 		//printf("Sum of the %d column of the matrix = %d\n",i+1,sum);
28 | 	}
29 | 	cout<<"Sum of the matrix elements = "<<sum<<endl;
30 | }
31 | 


--------------------------------------------------------------------------------
/Arrays/Arrays.cpp:
--------------------------------------------------------------------------------
  1 | #include<iostream>
  2 | #include <bits/stdc++.h> //Standard CPP Library
  3 | using namespace std;
  4 | int main()
  5 | {
  6 | 	int flag=0,ch,i,flag1=0,n,arr[100],flag2,el,pos;
  7 | 	for(i=0;i<100;i++)
  8 | 	{
  9 | 		arr[i]=0; //initializing the array to default value
 10 | 	}
 11 | 	cout<<"Code for Array Data Structure"<<endl;
 12 | 	do
 13 | 	{
 14 | 		cout<<"Option Menu\n\n";
 15 | 		cout<<"1) Creation of Array"<<endl;
 16 | 		cout<<"2) Insertion of element in the array"<<endl;
 17 | 		cout<<"3) Deletion of element in the array"<<endl;
 18 | 		cout<<"4) Searching an element in the array"<<endl;
 19 | 		cout<<"5) Sorting the array in Ascending Order"<<endl;
 20 | 		cout<<"6) Sorting the array in Descending Order"<<endl;
 21 | 		cout<<"7) Display the array"<<endl;
 22 | 		cout<<"8) Exit the Program"<<endl;
 23 | 		cout<<"Enter your choice: ";
 24 | 		cin>>ch;
 25 | 		cout<<"\n\n\n";
 26 | 		switch(ch)
 27 | 		{
 28 | 			case 1:
 29 | 				if(flag1==0)
 30 | 				{
 31 | 					flag1=1;
 32 | 					cout<<"Creation of Array"<<endl;
 33 | 					cout<<"Enter the size of the array you want to create :";
 34 | 					cin>>n;
 35 | 					for(i=0;i<n;i++)
 36 | 					{
 37 | 						cout<<"Enter the "<<i+1<<" element of the array: ";
 38 | 						cin>>arr[i];
 39 | 					}
 40 | 				}
 41 | 				else
 42 | 				{
 43 | 					cout<<"Array is already created!"<<endl;
 44 | 				}
 45 | 				break;
 46 | 			case 2:
 47 | 				if(flag1==0)
 48 | 				{
 49 | 					cout<<"Array not created and Insertion not possible!"<<endl;
 50 | 				}
 51 | 				else if(n==99)
 52 | 				{
 53 | 					cout<<"Array is full and no more insertion is possible"<<endl;
 54 | 				}
 55 | 				else
 56 | 				{
 57 | 					cout<<"Insertion in the array!"<<endl;
 58 | 					cout<<"Enter the position where you want to insert an element: ";
 59 | 					cin>>pos;
 60 | 					if(pos<0)
 61 | 					{
 62 | 						cout<<"Underflow Error"<<endl;
 63 | 					}
 64 | 					else if(pos>99)
 65 | 					{
 66 | 						cout<<"Overflow Error"<<endl;
 67 | 					}
 68 | 					else
 69 | 					{
 70 | 						pos = pos-1; //Position is index + 1
 71 | 						cout<<"Insertion is possible!"<<endl;
 72 | 						cout<<"Enter the element you want to insert: ";
 73 | 						cin>>el;
 74 | 						if(pos>=n)
 75 | 						{
 76 | 							arr[pos]=el;
 77 | 						}
 78 | 						else
 79 | 						{
 80 | 							//insertion between already created array elements
 81 | 							for(i=n-1;i>=pos;i--)
 82 | 							{
 83 | 								arr[i+1]=arr[i];
 84 | 							}
 85 | 							arr[pos]=el;
 86 | 						}
 87 | 						n++;
 88 | 					}
 89 | 				}
 90 | 				break;
 91 | 			case 3:
 92 | 				if(flag1==0)
 93 | 				{
 94 | 					cout<<"Array not created and deletion not possible"<<endl;
 95 | 				}
 96 | 				else
 97 | 				{
 98 | 					cout<<"Deletion of Element from the Array"<<endl;
 99 | 					cout<<"Enter the position from which you want to delete the array element: ";
100 | 					cin>>pos;
101 | 					pos=pos-1;
102 | 					if((pos<0)||(pos>=n))
103 | 					{
104 | 						cout<<"No element exists at the given position and thus deletion is not possible"<<endl;
105 | 					}
106 | 					else
107 | 					{
108 | 						arr[pos]=0;
109 | 					}
110 | 				}
111 | 				break;
112 | 			case 4:
113 | 				if(flag1==0)
114 | 				{
115 | 					cout<<"Array has not been created and thus searching is not possible!"<<endl;
116 | 				}
117 | 				else
118 | 				{
119 | 					flag2=0;
120 | 					cout<<"Searching for an element in the array"<<endl;
121 | 					cout<<"Enter the element you want to search in the array: ";
122 | 					cin>>el;
123 | 					for(i=0;i<n;i++)
124 | 					{
125 | 						if(arr[i]==el)
126 | 						{
127 | 							flag2=i+1;
128 | 							break;
129 | 						}
130 | 					}
131 | 					if(flag2==0)
132 | 					{
133 | 						cout<<"Element not found"<<endl;
134 | 					}
135 | 					else
136 | 					{
137 | 						cout<<"Element found at "<<flag2<<" position!"<<endl;
138 | 					}
139 | 				}
140 | 				break;
141 | 			case 5:
142 | 				if(flag1==0)
143 | 				{
144 | 					cout<<"Array not created and thus sorting is not possible"<<endl;
145 | 				}
146 | 				else
147 | 				{
148 | 					sort(arr,arr+n); //Using inbuilt sort function of CPP library
149 | 				}
150 | 				break;
151 | 			case 6:
152 | 				if(flag1==0)
153 | 				{
154 | 					cout<<"Array not created and thus sorting is not possible"<<endl;
155 | 				}
156 | 				else
157 | 				{
158 | 					sort(arr,arr+n,greater<int>()); //Using inbuilt sort function of CPP library
159 | 				}
160 | 				break;
161 | 			case 7:
162 | 				if(flag1==0)
163 | 				{
164 | 					cout<<"Array is not created and thus cannot be displayed!"<<endl;
165 | 				}
166 | 				else
167 | 				{
168 | 					cout<<"Displaying the array\n\n";
169 | 					for(i=0;i<n;i++)
170 | 					{
171 | 						cout<<"The "<<i+1<<" element of the array is: "<<arr[i]<<endl;
172 | 					}
173 | 				}
174 | 				break;
175 | 			case 8: flag =1;
176 | 				break;
177 | 			default: cout<<"Wrong Choice Entered!! Exiting the program"; flag = 1;
178 | 		}
179 | 		cout<<"\n\n\n";
180 | 	}while(flag!=1);
181 | 	cout<<"Thank You for using this program!";
182 | }
183 | 


--------------------------------------------------------------------------------
/Binary Trees/BFSTraversal.cpp:
--------------------------------------------------------------------------------
 1 | #include<iostream>
 2 | using namespace std;
 3 | class Tree
 4 | {
 5 | 	public:
 6 | 	int key;
 7 | 	Tree *left;
 8 | 	Tree *right;
 9 | 	void insert()
10 | 	{
11 | 		cout<<"Insert: ";
12 | 		cin>>key;
13 | 	}
14 | 	void show()
15 | 	{
16 | 		cout<<key<<endl;
17 | 	}	
18 | };
19 | int height(Tree *node)  
20 | {  
21 |     if (node == NULL)  
22 |         return 0;  
23 |     else
24 |     {  
25 |     	int lheight,rheight;
26 |     	lheight = height(node->left);  
27 |         rheight = height(node->right);  
28 |         if (lheight > rheight)
29 | 		{
30 | 			return(lheight + 1);
31 | 		}   
32 |         else return(rheight + 1);  
33 |     }  
34 | }
35 | void printGivenLevel(Tree *root, int level)  
36 | {  
37 |     if (root == NULL)  
38 |         return;  
39 |     if (level == 1)  
40 |         root->show();  
41 |     else if (level > 1)  
42 |     {  
43 |         printGivenLevel(root->left, level-1);  
44 |         printGivenLevel(root->right, level-1);  
45 |     }  
46 | }  
47 | void printLevelOrder(Tree *root)  
48 | {  
49 |     int h = height(root);  
50 |     int i;  
51 |     for (i = 1; i <= h; i++)  
52 |     printGivenLevel(root, i);  
53 | }  
54 | int main()
55 | {
56 | 	Tree *root;
57 | 	cout<<"Breadth First Traversal of Binary Tree"<<endl;
58 | 	cout<<"Enter Integer values when prompted"<<endl;
59 | 	root = new Tree;
60 | 	root->insert();
61 | 	root->left=NULL;
62 | 	root->right=NULL;
63 | 	root->left = new Tree;
64 | 	root->left->insert();
65 | 	root->left->left=NULL;
66 | 	root->left->right=NULL;
67 | 	root->right=new Tree;
68 | 	root->right->insert();
69 | 	root->right->right=NULL;
70 | 	root->right->left=NULL;
71 | 	//insertion over
72 | 	printLevelOrder(root);
73 | }
74 | 


--------------------------------------------------------------------------------
/Binary Trees/BinaryTrees.cpp:
--------------------------------------------------------------------------------
  1 | #include<iostream>
  2 | using namespace std;
  3 | class Tree
  4 | {
  5 | 	public:
  6 | 	int key;
  7 | 	Tree *left;
  8 | 	Tree *right;
  9 | 	void insert()
 10 | 	{
 11 | 		cout<<"Enter an Integer: ";
 12 | 		cin>>key;
 13 | 	}
 14 | 	void show()
 15 | 	{
 16 | 		cout<<key<<"\t\t";
 17 | 	}	
 18 | };
 19 | int height(Tree *node)  
 20 | {  
 21 |     if (node == NULL)  
 22 |         return 0;  
 23 |     else
 24 |     {  
 25 |     	int lheight,rheight;
 26 |     	lheight = height(node->left);  
 27 |         rheight = height(node->right);  
 28 |         if (lheight > rheight)
 29 | 		{
 30 | 			return(lheight + 1);
 31 | 		}   
 32 |         else return(rheight + 1);  
 33 |     }  
 34 | }
 35 | void printGivenLevel(Tree *root, int level)  
 36 | {  
 37 |     if (root == NULL)  
 38 |         return;  
 39 |     if (level == 1)  
 40 |     {
 41 |         root->show();  
 42 | 	}
 43 |     else if (level > 1)  
 44 |     {  
 45 |         printGivenLevel(root->left, level-1);  
 46 |         printGivenLevel(root->right, level-1);  
 47 |     }  
 48 | }  
 49 | void printLevelOrder(Tree *root)  
 50 | {  
 51 |     int h = height(root);  
 52 |     int i;  
 53 |     for (i = 1; i <= h; i++)  
 54 |     printGivenLevel(root, i);  
 55 | }  
 56 | void Inorder(Tree *node)
 57 | {
 58 | 	if(node==NULL)
 59 | 	{
 60 | 		return;
 61 | 	}
 62 | 	Inorder(node->left);
 63 | 	node->show();
 64 | 	Inorder(node->right);
 65 | }
 66 | void Preorder(Tree *node)
 67 | {
 68 | 	if(node==NULL)
 69 | 	{
 70 | 		return;
 71 | 	}
 72 | 	node->show();
 73 | 	Preorder(node->left);
 74 | 	Preorder(node->right);
 75 | }
 76 | void Postorder(Tree *node)
 77 | {
 78 | 	if(node==NULL)
 79 | 	{
 80 | 		return;
 81 | 	}
 82 | 	Postorder(node->left);
 83 | 	Postorder(node->right);
 84 | 	node->show();
 85 | }
 86 | /*
 87 | Tree *search(Tree *node,int el)
 88 | {
 89 | 	if(node==NULL)
 90 | 	{
 91 | 		return NULL;
 92 | 	}
 93 | 	search(node->left,el);
 94 | 	search(node->right,el);
 95 | 	if(node->key==el)
 96 | 	{
 97 | 		//cout<<node->key;
 98 | 		return node;
 99 | 	}
100 | }
101 | */
102 | int main()
103 | {
104 | 	Tree *root=NULL,*node,*ptr;
105 | 	int ch,flag=0,el,fleg,arr[100],i,ch1;
106 | 	//arr 100 contains a level order representation of elements of tree
107 | 	//left child on nth key is 2n+1
108 | 	//right child of nth key is 2n+2
109 | 	//0 value of array means node is NULL currently
110 | 	//Initializing the array
111 | 	for(i=0;i<100;i++)
112 | 	{
113 | 		arr[i]=0;
114 | 	}
115 | 	Tree *p[100]; //creating pointers for all the possible nodes!! overhead i know but solves the problem effectively
116 | 	for(i=0;i<100;i++)
117 | 	{
118 | 		p[i]=NULL;
119 | 	}
120 | 	cout<<"Binary Tree General Code";
121 | 	do
122 | 	{
123 | 		cout<<"\n\nOption Menu"<<endl;
124 | 		cout<<"1) Creation of Tree"<<endl;
125 | 		cout<<"2) Insertion"<<endl;
126 | 		cout<<"3) Inorder Traversal"<<endl;
127 | 		cout<<"4) Pre Order Traversal"<<endl;
128 | 		cout<<"5) Post Order Traversal"<<endl;
129 | 		cout<<"6) Level Order Traversal"<<endl;
130 | 		cout<<"7) Exit"<<endl;
131 | 		cout<<"Enter your choice: ";
132 | 		cin>>ch;
133 | 		cout<<"\n";
134 | 		switch(ch)
135 | 		{
136 | 			case 1:
137 | 				if(root==NULL)
138 | 				{
139 | 					cout<<"Creation of Root of Tree"<<endl;
140 | 					root = new Tree;
141 | 					root->insert();
142 | 					root->left=NULL;
143 | 					root->right=NULL;
144 | 					arr[0]=root->key;
145 | 					//cout<<arr[0];
146 | 					p[0]=root;
147 | 				}
148 | 				else
149 | 				{
150 | 					cout<<"Tree is already created!!"<<endl;
151 | 				}
152 | 				break;
153 | 			case 2:
154 | 				if(root==NULL)
155 | 				{
156 | 					cout<<"Tree does not exists"<<endl;
157 | 				}
158 | 				else
159 | 				{
160 | 					cout<<"Insertion in the Tree"<<endl;
161 | 					cout<<"Enter the element whose child you want to insert: ";
162 | 					cin>>el;
163 | 					fleg=-1;
164 | 					for(i=0;i<100;i++)
165 | 					{
166 | 						if(arr[i]==el)
167 | 						{
168 | 							fleg=i;
169 | 							break;
170 | 						}
171 | 					}
172 | 					if(fleg==(-1))
173 | 					{
174 | 						cout<<"Element does not exist in the tree!\nCannot perform Insertion!"<<endl;
175 | 					}
176 | 					else
177 | 					{
178 | 						cout<<"Element Found!\nChecking for empty child nodes\n";
179 | 						if((p[i]->left==NULL)&&(p[i]->right==NULL))
180 | 						{
181 | 							cout<<"Both the nodes are empty! Enter 1 for left and 2 for right: ";
182 | 							cin>>ch1;
183 | 							if(ch1==1)
184 | 							{
185 | 								cout<<"Insertion at Left"<<endl;
186 | 								node = new Tree;
187 | 								node->insert();
188 | 								node->left=NULL;
189 | 								node->right=NULL;
190 | 								p[i]->left=node;
191 | 								p[(2*i)+1]=node;
192 | 								arr[(2*i)+1]=node->key;
193 | 							}
194 | 							else if(ch1==2)
195 | 							{
196 | 								cout<<"Insertion at Right"<<endl;
197 | 								node = new Tree;
198 | 								node->insert();
199 | 								node->left=NULL;
200 | 								node->right=NULL;
201 | 								p[i]->right=node;
202 | 								p[(2*i)+2]=node;
203 | 								arr[(2*i)+2]=node->key;
204 | 							}
205 | 							else
206 | 							{
207 | 								cout<<"Invalid Choice! Cannot insert\n";
208 | 							}
209 | 						}
210 | 						else if((p[i]->left==NULL)&&(p[i]->right!=NULL))
211 | 						{
212 | 							cout<<"Insertion at Left"<<endl;
213 | 							node = new Tree;
214 | 							node->insert();
215 | 							node->left=NULL;
216 | 							node->right=NULL;
217 | 							p[i]->left=node;
218 | 							p[(2*i)+1]=node;
219 | 							arr[(2*i)+1]=node->key;
220 | 						}
221 | 						else if((p[i]->left!=NULL)&&(p[i]->right==NULL))
222 | 						{
223 | 							cout<<"Insertion at Right"<<endl;
224 | 							node = new Tree;
225 | 							node->insert();
226 | 							node->left=NULL;
227 | 							node->right=NULL;
228 | 							p[i]->right=node;
229 | 							p[(2*i)+2]=node;
230 | 							arr[(2*i)+2]=node->key;
231 | 						}
232 | 						else if((p[i]->left!=NULL)&&(p[i]->right!=NULL))
233 | 						{
234 | 							cout<<"Both children exists and Insertion is not possible\n";
235 | 						}
236 | 					}
237 | 				}
238 | 				break;
239 | 			case 3:
240 | 				if(root==NULL)
241 | 				{
242 | 					cout<<"Tree does not exists"<<endl;
243 | 				}
244 | 				else
245 | 				{
246 | 					cout<<"Inorder Tree Traversal\n\n";
247 | 					Inorder(root);
248 | 				}
249 | 				break;
250 | 			case 4:
251 | 				if(root==NULL)
252 | 				{
253 | 					cout<<"Tree does not exist"<<endl;
254 | 				}
255 | 				else
256 | 				{
257 | 					cout<<"Pre Order Tree Traversal\n\n";
258 | 					Preorder(root);
259 | 				}
260 | 				break;
261 | 			case 5:
262 | 				if(root==NULL)
263 | 				{
264 | 					cout<<"Tree does not exist"<<endl;
265 | 				}
266 | 				else
267 | 				{
268 | 					cout<<"Post order Tree Traversal\n\n";
269 | 					Postorder(root);
270 | 				}
271 | 				break;
272 | 			case 6:
273 | 				if(root==NULL)
274 | 				{
275 | 					cout<<"Tree does not exist"<<endl;
276 | 				}
277 | 				else
278 | 				{
279 | 					cout<<"Level Order Tree Traversal\n\n";
280 | 					printLevelOrder(root);
281 | 				}
282 | 				break;
283 | 			case 7:
284 | 				flag=1;
285 | 				break;
286 | 			default: cout<<"Wrong choice entered!! Exiting the program"<<endl; flag=1;
287 | 		}
288 | 		
289 | 	}while(flag==0);
290 | 	cout<<"Thank you for using the code"<<endl;
291 | }
292 | 
293 | 


--------------------------------------------------------------------------------
/Binary Trees/InorderTraversal.cpp:
--------------------------------------------------------------------------------
 1 | #include<iostream>
 2 | using namespace std;
 3 | class Tree
 4 | {
 5 | 	public:
 6 | 	int key;
 7 | 	Tree *left;
 8 | 	Tree *right;
 9 | 	void insert()
10 | 	{
11 | 		cout<<"Insert: ";
12 | 		cin>>key;
13 | 	}
14 | 	void show()
15 | 	{
16 | 		cout<<key<<endl;
17 | 	}	
18 | };
19 | void print(Tree *node)
20 | {
21 | 	if(node==NULL)
22 | 	{
23 | 		return;
24 | 	}
25 | 	print(node->left);
26 | 	node->show();
27 | 	print(node->right);
28 | }
29 | int main()
30 | {
31 | 	Tree *root;
32 | 	cout<<"InOrder Traversal of Binary Tree"<<endl;
33 | 	cout<<"Enter Integer values when prompted"<<endl;
34 | 	root = new Tree;
35 | 	root->insert();
36 | 	root->left=NULL;
37 | 	root->right=NULL;
38 | 	root->left = new Tree;
39 | 	root->left->insert();
40 | 	root->left->left=NULL;
41 | 	root->left->right=NULL;
42 | 	root->right=new Tree;
43 | 	root->right->insert();
44 | 	root->right->right=NULL;
45 | 	root->right->left=NULL;
46 | 	//insertion over
47 | 	print(root);
48 | }


--------------------------------------------------------------------------------
/Binary Trees/PostOrderTraversal.cpp:
--------------------------------------------------------------------------------
 1 | #include<iostream>
 2 | using namespace std;
 3 | class Tree
 4 | {
 5 | 	public:
 6 | 	int key;
 7 | 	Tree *left;
 8 | 	Tree *right;
 9 | 	void insert()
10 | 	{
11 | 		cout<<"Insert: ";
12 | 		cin>>key;
13 | 	}
14 | 	void show()
15 | 	{
16 | 		cout<<key<<endl;
17 | 	}	
18 | };
19 | void print(Tree *node)
20 | {
21 | 	if(node==NULL)
22 | 	{
23 | 		return;
24 | 	}
25 | 	print(node->left);
26 | 	print(node->right);
27 | 	node->show();
28 | }
29 | int main()
30 | {
31 | 	Tree *root;
32 | 	cout<<"Post Order Traversal of Binary Tree"<<endl;
33 | 	cout<<"Enter Integer values when prompted"<<endl;
34 | 	root = new Tree;
35 | 	root->insert();
36 | 	root->left=NULL;
37 | 	root->right=NULL;
38 | 	root->left = new Tree;
39 | 	root->left->insert();
40 | 	root->left->left=NULL;
41 | 	root->left->right=NULL;
42 | 	root->right=new Tree;
43 | 	root->right->insert();
44 | 	root->right->right=NULL;
45 | 	root->right->left=NULL;
46 | 	//insertion over
47 | 	print(root);
48 | }
49 | 


--------------------------------------------------------------------------------
/Binary Trees/PreOrderTraversal.cpp:
--------------------------------------------------------------------------------
 1 | #include<iostream>
 2 | using namespace std;
 3 | class Tree
 4 | {
 5 | 	public:
 6 | 	int key;
 7 | 	Tree *left;
 8 | 	Tree *right;
 9 | 	void insert()
10 | 	{
11 | 		cout<<"Insert: ";
12 | 		cin>>key;
13 | 	}
14 | 	void show()
15 | 	{
16 | 		cout<<key<<endl;
17 | 	}	
18 | };
19 | void print(Tree *node)
20 | {
21 | 	if(node==NULL)
22 | 	{
23 | 		return;
24 | 	}
25 | 	node->show();
26 | 	print(node->left);
27 | 	print(node->right);
28 | }
29 | int main()
30 | {
31 | 	Tree *root;
32 | 	cout<<"Pre Order Traversal of Binary Tree"<<endl;
33 | 	cout<<"Enter Integer values when prompted"<<endl;
34 | 	root = new Tree;
35 | 	root->insert();
36 | 	root->left=NULL;
37 | 	root->right=NULL;
38 | 	root->left = new Tree;
39 | 	root->left->insert();
40 | 	root->left->left=NULL;
41 | 	root->left->right=NULL;
42 | 	root->right=new Tree;
43 | 	root->right->insert();
44 | 	root->right->right=NULL;
45 | 	root->right->left=NULL;
46 | 	//insertion over
47 | 	print(root);
48 | }
49 | 


--------------------------------------------------------------------------------
/CONTRIBUTING.md:
--------------------------------------------------------------------------------
 1 | # How to Collaborate:
 2 | 
 3 | 1. Fork the repository to your own GitHub account.
 4 | 
 5 | 2. Clone the repository to your local machine
 6 | ```
 7 | $ git clone "https://www.github.com/{Username}/Data-Structures.git"
 8 | ```
 9 | where username is your GitHub account username.
10 | 
11 | 3. Create a branch where you can do your local work.
12 | Never work on **master** branch as we do not allow master commits except by admins.
13 | ```
14 | $ git branch {branchname}
15 | $ git checkout branchname
16 | ```
17 | 
18 | 4. Do your work and stage your changes.
19 | ```
20 | $ git add <filename>
21 | ```
22 | 
23 | 5. Commit you changes with a commit message containing your name, file(s) worked upon, changes added.
24 | ```
25 | $ git commit -m "Name| files| Changes"
26 | ```
27 | 
28 | 6. Push changes to your forked repository
29 | ```
30 | $ git push -u origin branchname
31 | ```
32 | 
33 | # Synchronize forked repository with Upstream repository
34 | 
35 | 1. Create upstream as our repository
36 | ```
37 | $ git remote add upstream "https://www.github.com/NishkarshRaj/Data-Structures.git"
38 | ```
39 | 
40 | 2. Fetch upstream changes in local machine
41 | ```
42 | $ git fetch upstream
43 | ```
44 | 
45 | 3. Switch to master branch
46 | ```
47 | $ git checkout master
48 | ```
49 | 
50 | 4. Merge changes in local machine
51 | ```
52 | $ git merge upstream/master
53 | ```
54 | 
55 | 5. Push changes to your forked GitHub repository
56 | ```
57 | $ git push -f origin master
58 | ```
59 | 
60 | 


--------------------------------------------------------------------------------
/LICENSE:
--------------------------------------------------------------------------------
  1 |                     GNU GENERAL PUBLIC LICENSE
  2 |                        Version 3, 29 June 2007
  3 | 
  4 |  Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
  5 |  Everyone is permitted to copy and distribute verbatim copies
  6 |  of this license document, but changing it is not allowed.
  7 | 
  8 |                             Preamble
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  1 | <html>
  2 | <head>
  3 | <title> Data Structures and Algorithms </title>
  4 | <style>
  5 | h1#header {text-align:center;}
  6 | h2 {text-align:center;}
  7 | div {margin-left:10px;}
  8 | pre.edit {color:white;background-color:black; margin-left:10px; margin-right:10px;}
  9 | button#Reference {
 10 | background-color: blue;
 11 | color: white;
 12 | border: 2px solid black;
 13 | margin-left:530px;
 14 | margin-right:500px;
 15 | margin-bottom:40px;
 16 | width:300px;
 17 | display:inline-block;
 18 | text-align:center;
 19 | padding: 5px;
 20 | outline: 2px solid white;
 21 | }
 22 | </style>
 23 | </head>
 24 | <body>
 25 | <u><h1 id="header"> Doubly Linked List </h1></u>
 26 | <h3 style="text-align:center;"><mark>Reading time: 20 minutes | Coding time: 15 minutes</h3></mark>
 27 | <div id=menu>
 28 | <ol>
 29 | <li><a href=#theory> Theory</a></li>
 30 | <li><a href=#complexity> Complexity</a></li>
 31 | <li><a href=#implementation> Implementation</a></li>
 32 | <li><a href=#application> Applications</a></li>
 33 | <li><a href=#advantages> Advantages</a></li>
 34 | <li><a href=#disadvantage> Disadvantages</a></li>
 35 | <li><a href=#question> Question</a></li>
 36 | <li><a href=#Reference> Reference</a></li>
 37 | </div>
 38 | <div id="theory">
 39 | <u><h2>Theory</h2></u>
 40 | <pre>
 41 | A Doubly Linked List is a Linked List which has connection pointer to each of its previous element and is generally defined as "prev"
 42 | 
 43 | Thus, a node in Doubly Linked Pointer consists of following:
 44 | 
 45 | 	1) next pointer => contains the address of next node of the DLL.
 46 | 	2) data elements => contains the information of the node of DLL.
 47 | 	3) prev pointer => contains the address of the previous node of the DLL.
 48 | 
 49 | <b>Declaration:
 50 | class classname
 51 | {
 52 | datatype data1,....; //data elements
 53 | classname *next; //next pointer
 54 | classname *prev; //previous pointer
 55 | }
 56 | </b>
 57 | </pre>
 58 | <img src="dll.png" alt="Need Internet for Image" style="margin-left:500px;margin-right:500px;border:2px solid black;"> <br>
 59 | <img src="compare.png" style="margin-left:500px;margin-right:500px;border:2px solid black;margin-top:5px;">
 60 | </div>
 61 | <div id="complexity">
 62 | <u><h2>Complexity</h2></u>
 63 | <ol>
 64 | <li>Insertion</li>
 65 | <ul>
 66 | <li>Worst case time complexity <b>O(n)</b></li>
 67 | <li>Best case time complexity <b>O(1)</b></li>
 68 | <li>Average case time complexity <b>O(1)</b></li>
 69 | <li>Space complexity <b>O(1)</b></li>
 70 | </ul>
 71 | <li>Deletion</li>
 72 | <ul>
 73 | <li>Worst case time complexity <b>O(n)</b></li>
 74 | <li>Best case time complexity <b>O(1)</b></li>
 75 | <li>Average case time complexity <b>O(1)</b></li>
 76 | <li>Space complexity <b>O(1)</b></li>
 77 | </ul>
 78 | <li>Display</li>
 79 | <ul>
 80 | <li>Worst case time complexity <b>O(n)</b></li>
 81 | <li>Best case time complexity <b>O(n)</b></li>
 82 | <li>Average case time complexity <b>O(n)</b></li>
 83 | <li>Space complexity <b>O(1)</b></li>
 84 | </ul>
 85 | </ol>
 86 | </div>
 87 | <u><h2 id="implementation">Implementation</h2></u>
 88 | <img src="Code1.png" alt="Need Internet to get Image"> <br>
 89 | <img src="Code2.png"><br>
 90 | <img src="Code3.png"><br>
 91 | <img src="Code4.png"><br>
 92 | <img src="Code5.png"><br>
 93 | </div>
 94 | <div id="application">
 95 | <u><h2>Applications of Doubly Linked List</h2></u>
 96 | <ol>
 97 | <li>Redo-Undo options</li>
 98 | <li>Navigating next/previous pages on Web</li>
 99 | <li>Sorting history by most recent.</li>
100 | </ol>
101 | </div>
102 | <div id="advantages">
103 | <u><h2>Advantages of Doubly Linked List</h2></u>
104 | <ol>
105 | <li>A Doubly linked list can be traversed from both its head and its tail.</li>
106 | <li>Deletion Operations becomes efficient and uses less memory.</li>
107 | <li>For a sorted Doubly Linked list, it is more efficient to traverse from nearest end.</li>
108 | </ol>
109 | </div>
110 | <div id="disadvantage">
111 | <u><h2>Disadvantages of Doubly Linked List</h2></u>
112 | <ol>
113 | <li>It uses one extra pointer for all the nodes, thus increasing the space complexity and security concerns.</li>
114 | <li>Handling large number of pointers while performing deletion is very tedious.</li>
115 | </ol>
116 | </div>
117 | <div id="question">
118 | <u><h2>Question</h2></u>
119 | <h4>What is the complexity of insertion of a node in Doubly Linked List?</h4>
120 | <button onclick="correct()" margin:auto; display:block;> 1) O(n)   </button> <br>
121 | <button onclick="incorrect()" margin:auto; display:block;> 2) O(1)   </button> <br>
122 | <button onclick="incorrect()" margin:auto; display:block;> 3) O(n<sup>2</sup>)</button> <br>
123 | <button onclick="incorrect()" margin:auto; display:block;> 4) O(2<sup>n</sup>)</button> <br>
124 | <div id="incorrect" style="display:none;">
125 | <pre class="edit">Incorrect Answer.
126 | Please Try another option. </pre>
127 | </div>
128 | <div id="correct" style="display:none;">
129 | <pre class="edit">Correct Answer!
130 | Explanation: For Insertion in Linked List, we have to traverse the list first.
131 | Complexity of Traversal = <b>O(n)</b>
132 | Complexity of Insertion of one node = <b>O(1)</b>
133 | Total Complexity = <b>O(n) + O(1) = <mark>O(n)</mark></b> </pre>
134 | </div>
135 | </div>
136 | <br>
137 | <a target="_blank" href="https://github.com/NishkarshRaj/Data-Structures/blob/master/Linked%20List/DoublyLinkedList.cpp">
138 | <button id="Reference">
139 | Check this code at GitHub
140 | </button>
141 | </a>
142 | <script>
143 | function correct()
144 | {
145 | document.getElementById("correct").style.display = "block";
146 | document.getElementById("incorrect").style.display = "none";
147 | }
148 | function incorrect()
149 | {
150 | document.getElementById("incorrect").style.display = "block";
151 | document.getElementById("correct").style.display = "none";
152 | }
153 | </script>
154 | </body>
155 | </html>


--------------------------------------------------------------------------------
/Linked List/DoublyLinkedList.cpp:
--------------------------------------------------------------------------------
  1 | #include<iostream>
  2 | using namespace std;
  3 | class linked
  4 | {
  5 | 	public:
  6 | 	linked *prev;
  7 | 	int key;
  8 | 	linked *next;
  9 | 	void insert()
 10 | 	{
 11 | 		cin>>key;
 12 | 	}
 13 | 	void show()
 14 | 	{
 15 | 		cout<<key;
 16 | 	}
 17 | };
 18 | int main()
 19 | {
 20 | 	linked *start,*end,*node,*ptr,*p;
 21 | 	int flag=0,ch,count=0,travel,pos;
 22 | 	start=NULL;
 23 | 	cout<<"Doubly Linked List code!"<<endl;
 24 | 	do
 25 | 	{
 26 | 		cout<<"\n\n";
 27 | 		cout<<"Option Menu"<<endl;
 28 | 		cout<<"1) Creation of Linked List"<<endl;
 29 | 		cout<<"2) Insertion at start"<<endl;
 30 | 		cout<<"3) Insertion at end"<<endl;
 31 | 		cout<<"4) Insertion at any point"<<endl;
 32 | 		cout<<"5) Deletion at start"<<endl;
 33 | 		cout<<"6) Deletion at end"<<endl;
 34 | 		cout<<"7) Deletion at any point"<<endl;
 35 | 		cout<<"8) Traversal from start"<<endl;
 36 | 		cout<<"9) Traversal from end"<<endl;
 37 | 		cout<<"10) Exit the program"<<endl;
 38 | 		cout<<"Enter your choice: ";
 39 | 		cin>>ch;
 40 | 		cout<<"\n";
 41 | 		switch(ch)
 42 | 		{
 43 | 			case 1:
 44 | 				if(start==NULL)
 45 | 				{
 46 | 					cout<<"Creation of Linked List"<<endl;
 47 | 					node = new linked;
 48 | 					node->insert();
 49 | 					node->next=NULL;
 50 | 					node->prev=NULL;
 51 | 					start=node;
 52 | 					end=node;
 53 | 					count++;
 54 | 				}
 55 | 				else
 56 | 				{
 57 | 					cout<<"Linked list is already created!"<<endl;
 58 | 				}
 59 | 				break;
 60 | 			case 2:
 61 | 				if(start!=NULL)
 62 | 				{
 63 | 					cout<<"Insertion at beginning"<<endl;
 64 | 					node = new linked;
 65 | 					node->insert();
 66 | 					node->next=start;
 67 | 					node->prev=NULL;
 68 | 					start->prev=node;
 69 | 					start=node;
 70 | 					count++;
 71 | 				}
 72 | 				else
 73 | 				{
 74 | 					cout<<"Insertion is not possible because Linked list is not created!"<<endl;
 75 | 				}
 76 | 				break;
 77 | 			case 3:
 78 | 				if(start!=NULL)
 79 | 				{
 80 | 					cout<<"Insertion at end"<<endl;
 81 | 					node = new linked;
 82 | 					node->insert();
 83 | 					node->prev=end;
 84 | 					end->next=node;
 85 | 					node->next=NULL;
 86 | 					end=node;
 87 | 					count++;
 88 | 				}
 89 | 				else
 90 | 				{
 91 | 					cout<<"Insertion not possible because linked list is not created"<<endl;
 92 | 				}
 93 | 				break;
 94 | 			case 4:
 95 | 				if(start!=NULL)
 96 | 				{
 97 | 					cout<<"Enter the position of insertion except 1 : ";
 98 | 					cin>>pos;
 99 | 					if(pos<=count)
100 | 					{
101 | 						node= new linked;
102 | 						node->insert();
103 | 						ptr=start;
104 | 						pos=pos-2;
105 | 						while(pos--)
106 | 						{
107 | 							ptr=ptr->next;
108 | 						}
109 | 						node->next=ptr->next;
110 | 						ptr->next=node;
111 | 						node->prev=ptr;
112 | 						count++;
113 | 					}
114 | 					else
115 | 					{
116 | 						cout<<"Position exceeds count which is impossible!!"<<endl;
117 | 					}
118 | 				}
119 | 				else
120 | 				{
121 | 					cout<<"Insertion not possible because Linked list is not created or is empty!"<<endl;
122 | 				}
123 | 				break;
124 | 			case 5:
125 | 				if(count>1)
126 | 				{
127 | 					cout<<"Deletion at start"<<endl;
128 | 					ptr=start;
129 | 					start=ptr->next;
130 | 					start->prev=NULL;
131 | 					delete ptr;
132 | 					count--;
133 | 				}
134 | 				else if(count==1)
135 | 				{
136 | 					ptr=start;
137 | 					start=NULL;
138 | 					end=NULL;
139 | 					delete ptr;
140 | 				}
141 | 				else if(count==0)
142 | 				{
143 | 					cout<<"Linked list is empty"<<endl;
144 | 				}
145 | 				else
146 | 				{
147 | 					cout<<"Deletion not possible because linked list is not created"<<endl;
148 | 				}
149 | 				break;
150 | 			case 6:
151 | 				if(count>1)
152 | 				{
153 | 					ptr=end;
154 | 					end=ptr->prev;
155 | 					end->next=NULL;
156 | 					delete ptr;
157 | 					count--;
158 | 				}
159 | 				else if(count==1)
160 | 				{
161 | 					ptr=start;
162 | 					start=NULL;
163 | 					end=NULL;
164 | 					delete ptr;
165 | 				}
166 | 				else if(count==0)
167 | 				{
168 | 					cout<<"Empty Linked list! Deletion not possible"<<endl;
169 | 				}
170 | 				else
171 | 				{
172 | 					cout<<"Linked list not created!! Deletion not possible!"<<endl;
173 | 				}
174 | 				break;
175 | 			case 7:
176 | 				if(start!=NULL)
177 | 				{
178 | 					cout<<"Enter position to delete!: ";
179 | 					cin>>pos;
180 | 					pos=pos-1;
181 | 					ptr=start;
182 | 					while(pos--)
183 | 					{
184 | 						ptr=ptr->next;
185 | 					}
186 | 					node=ptr->prev;
187 | 					p=ptr->next;
188 | 					node->next=p;
189 | 					p->prev=node;
190 | 					delete ptr;
191 | 					count--;
192 | 				}
193 | 				else
194 | 				{
195 | 					cout<<"Deletion not possible because Linked list does not exist"<<endl;
196 | 				}
197 | 				break;
198 | 			case 8:
199 | 				if(start!=NULL)
200 | 				{
201 | 					cout<<"Traversal from start"<<endl;
202 | 					ptr=start;
203 | 					travel=count;
204 | 					while(travel--)
205 | 					{
206 | 						ptr->show();
207 | 						cout<<"\t";
208 | 						ptr=ptr->next;
209 | 					}
210 | 				}
211 | 				else
212 | 				{
213 | 					cout<<"Cannot perform traversal because Linked list is not created or is empty!"<<endl;
214 | 				}
215 | 				break;
216 | 			case 9:
217 | 				if(start!=NULL)
218 | 				{
219 | 					cout<<"Traversal from end"<<endl;
220 | 					ptr=end;
221 | 					travel=count;
222 | 					while(travel--)
223 | 					{
224 | 						ptr->show();
225 | 						cout<<"\t";
226 | 						ptr=ptr->prev;
227 | 					}
228 | 				}
229 | 				break;
230 | 			case 10:
231 | 				flag=1;
232 | 				break;
233 | 			default: cout<<"Wrong choice! Exiting program"<<endl; flag=1;
234 | 		}
235 | 	}while(flag==0);
236 | 	cout<<"Thankyou for using the program"<<endl;
237 | }
238 | 


--------------------------------------------------------------------------------
/Linked List/LinkedList.cpp:
--------------------------------------------------------------------------------
  1 | #include<iostream>
  2 | using namespace std;
  3 | class linkedlist
  4 | {
  5 | 	public:
  6 | 		int key;
  7 | 		char value;
  8 | 		string name;
  9 | 		linkedlist *next;
 10 | 		linkedlist()
 11 | 		{
 12 | 			key=0;
 13 | 			value='a';
 14 | 			name="Name";
 15 | 		}
 16 | 		void insertion()
 17 | 		{
 18 | 			cout<<"Enter the Key value of Link: ";
 19 | 			cin>>key;
 20 | 			cout<<"Enter the Character value of the Link: ";
 21 | 			cin>>value;
 22 | 			cout<<"Enter the name of the Link: ";
 23 | 			cin.ignore(); //This is used because of switching from normal data type to string the first switch does not count because of linefeed
 24 | 			getline(cin,name);
 25 | 		}
 26 | 		void display()
 27 | 		{
 28 | 			cout<<"Key value of the Link is: "<<key<<endl;
 29 | 			cout<<"Value of the Link is: "<<value<<endl;
 30 | 			cout<<"Name of the Link is: "<<name<<endl;
 31 | 		}
 32 | };
 33 | int main()
 34 | {
 35 | 	linkedlist *node,*ptr,*start,*p;
 36 | 	int flag=0,flag1=0,ch,travel,pos,count=0,d; //count counts the total number of links created till now
 37 | 	cout<<"Basic Single Linked List Code"<<endl;
 38 | 	do
 39 | 	{
 40 | 		cout<<"Option Menu"<<endl;
 41 | 		cout<<"1) Creation of Linked List"<<endl;
 42 | 		cout<<"2) Insertion at beginning"<<endl;
 43 | 		cout<<"3) Insertion at the End"<<endl;
 44 | 		cout<<"4) Insertion at any point"<<endl;
 45 | 		cout<<"5) Deletion from beginning"<<endl;
 46 | 		cout<<"6) Deletion from end"<<endl;
 47 | 		cout<<"7) Deletion from any point"<<endl;
 48 | 		cout<<"8) Traversal of Linked List"<<endl;
 49 | 		cout<<"9) Exit the program"<<endl;
 50 | 		cout<<"Enter your choice: ";
 51 | 		cin>>ch;
 52 | 		cout<<"\n\n";
 53 | 		switch(ch)
 54 | 		{
 55 | 			case 1:
 56 | 				if(flag1!=0)
 57 | 				{
 58 | 					cout<<"Linked List already created!"<<endl;
 59 | 				}
 60 | 				else
 61 | 				{
 62 | 					cout<<"Creation of Linked List\n\n";
 63 | 					cout<<"Create the first node of the Linked List\n";
 64 | 					flag1 = 1;
 65 | 					node = new linkedlist;
 66 | 					node->insertion();
 67 | 					node->next=NULL;
 68 | 					start=node;
 69 | 					count++;
 70 | 				}
 71 | 				break;
 72 | 			case 2:
 73 | 				if(flag1==0)
 74 | 				{
 75 | 					cout<<"Linked list is not created!!"<<endl;
 76 | 				}
 77 | 				else
 78 | 				{
 79 | 					cout<<"Insertion at beginning"<<endl;
 80 | 					node = new linkedlist;
 81 | 					node->insertion();
 82 | 					node->next=start;
 83 | 					start=node;
 84 | 					count++;
 85 | 				}
 86 | 				break;
 87 | 			case 3:
 88 | 				if(flag1==0)
 89 | 				{
 90 | 					cout<<"Linked list is not created"<<endl;
 91 | 				}
 92 | 				else
 93 | 				{
 94 | 					cout<<"Insertion of link at the end of the list"<<endl;
 95 | 					node = new linkedlist;
 96 | 					node->insertion();
 97 | 					node->next=NULL;
 98 | 					for(ptr=start;ptr->next!=NULL;ptr=ptr->next);
 99 | 					ptr->next=node;
100 | 					count++;
101 | 				}
102 | 				break;
103 | 			case 4:
104 | 				if(flag1==0)
105 | 				{
106 | 					cout<<"Linked list is not created!"<<endl;
107 | 				}
108 | 				else
109 | 				{
110 | 					cout<<"Insertion at any point"<<endl;
111 | 					cout<<"Enter the position where you want to insert the link: ";
112 | 					cin>>pos;
113 | 					if(pos<1)
114 | 					{
115 | 						cout<<"Insertion not possible due to underflow"<<endl;
116 | 					}
117 | 					else if(pos>(count+1))
118 | 					{
119 | 						cout<<"Insertion not possible due to overflow";
120 | 					}
121 | 					else if(pos==1)
122 | 					{
123 | 						//insertion at beginning
124 | 						node = new linkedlist;
125 | 						node->insertion();
126 | 						node->next=start;
127 | 						start=node;
128 | 						count++;
129 | 					}
130 | 					else if(pos==count+1)
131 | 					{
132 | 						//insertion at end
133 | 						node = new linkedlist;
134 | 						node->insertion();
135 | 						node->next=NULL;
136 | 						for(ptr=start;ptr->next!=NULL;ptr=ptr->next);
137 | 						ptr->next=node;
138 | 						count++;
139 | 					}
140 | 					else
141 | 					{
142 | 						d=1;
143 | 						for(ptr=start;d<pos-1;ptr=ptr->next)
144 | 						{
145 | 							d++;
146 | 						}
147 | 						node = new linkedlist;
148 | 						node->insertion();
149 | 						node->next=ptr->next;
150 | 						ptr->next=node;
151 | 						count++;
152 | 					}
153 | 				}
154 | 				break;
155 | 			case 5:
156 | 				if(flag1==0)
157 | 				{
158 | 					cout<<"Linked list is not created"<<endl;
159 | 				}
160 | 				else
161 | 				{
162 | 					cout<<"Deletion from beginning"<<endl;
163 | 					ptr = start;
164 | 					start = ptr->next;
165 | 					delete ptr;
166 | 					count--;
167 | 				}
168 | 				break;
169 | 			case 6:
170 | 				if(flag1==0)
171 | 				{
172 | 					cout<<"Linked list is not created\n";
173 | 				}
174 | 				else
175 | 				{
176 | 					for(ptr=start;ptr->next!=NULL;p=ptr,ptr=ptr->next);
177 | 					p->next=NULL;
178 | 					delete ptr;
179 | 					count--;
180 | 				}
181 | 				break;
182 | 			case 7:
183 | 				if(flag1==0)
184 | 				{
185 | 					cout<<"Linked List is not created"<<endl;
186 | 				}
187 | 				else
188 | 				{
189 | 					cout<<"Deletion at any point"<<endl;
190 | 					cout<<"Enter the position where you want to delete the node: ";
191 | 					cin>>pos;
192 | 					if(pos<1)
193 | 					{
194 | 						cout<<"Deletion impossible because of underflow"<<endl;
195 | 					}
196 | 					else if(pos>count)
197 | 					{
198 | 						cout<<"Deletion impossible due to overflow"<<endl;
199 | 					}
200 | 					else if(pos==1)
201 | 					{
202 | 						//deletion from beginning
203 | 						ptr = start;
204 | 						start = ptr->next;
205 | 						delete ptr;
206 | 						count--;
207 | 					}
208 | 					else if(pos == count)
209 | 					{
210 | 						//deletion from end
211 | 						for(ptr=start;ptr->next!=NULL;p=ptr,ptr=ptr->next);
212 | 						p->next=NULL;
213 | 						delete ptr;
214 | 						count--;
215 | 					}
216 | 					else
217 | 					{
218 | 						ptr=start;
219 | 						pos--;
220 | 						while(pos--)
221 | 						{
222 | 							p=ptr;
223 | 							ptr=ptr->next;
224 | 						}
225 | 						p->next=ptr->next;
226 | 						delete ptr;
227 | 						count--;
228 | 					}
229 | 				}
230 | 				break;
231 | 			case 8: 
232 | 				if(flag1==0)
233 | 				{
234 | 					cout<<"Linked List not created!"<<endl;
235 | 				}
236 | 				else
237 | 				{
238 | 					cout<<"Linked List Traversal\n\n";
239 | 					travel=0;
240 | 					for(ptr=start;ptr!=NULL;ptr=ptr->next)
241 | 					{
242 | 						cout<<++travel<<" Link of the List is\n";
243 | 						ptr->display();
244 | 						cout<<"\n";
245 | 					}
246 | 				}
247 | 				break;
248 | 			case 9:
249 | 				flag = 1;
250 | 				break;
251 | 			default: cout<<"Wrong choice Entered!! Exiting program"; flag=1;
252 | 		}
253 | 		cout<<"\n\n";
254 | 	}while(flag!=1);
255 | 	cout<<"\nThank you for using the program"<<endl;
256 | }
257 | 


--------------------------------------------------------------------------------
/Linked List/LinkedList_Array.cpp:
--------------------------------------------------------------------------------
  1 | #include<iostream>
  2 | using namespace std;
  3 | int main()
  4 | {
  5 | 	int flag=0,ch,n,i,max,flag1=0,el,pos;
  6 | 	cout<<"Array Implementation of Linked List"<<endl;
  7 | 	cout<<"Enter the max size of array you want to use: ";
  8 | 	cin>>max;
  9 | 	int arr[max];
 10 | 	for(i=0;i<max;i++)
 11 | 	{
 12 | 		arr[i] = 0;
 13 | 	}
 14 | 	do
 15 | 	{
 16 | 		cout<<"Option Menu"<<endl;
 17 | 		cout<<"1) Creation of Linked List"<<endl;
 18 | 		cout<<"2) Insertion at beginning"<<endl;
 19 | 		cout<<"3) Insertion at the End"<<endl;
 20 | 		cout<<"4) Insertion at any point"<<endl;
 21 | 		cout<<"5) Deletion from beginning"<<endl;
 22 | 		cout<<"6) Deletion from end"<<endl;
 23 | 		cout<<"7) Deletion from any point"<<endl;
 24 | 		cout<<"8) Traversal of Linked List"<<endl;
 25 | 		cout<<"9) Exit the program"<<endl;
 26 | 		cout<<"Enter your choice: ";
 27 | 		cin>>ch;
 28 | 		cout<<"\n\n";
 29 | 		switch(ch)
 30 | 		{
 31 | 			case 1:
 32 | 				if(flag1==0)
 33 | 				{
 34 | 					cout<<"Creation of Linked List"<<endl;
 35 | 					cout<<"Enter the number of elements you want in the Linked List: ";
 36 | 					cin>>n;
 37 | 					if(n<=max)
 38 | 					{
 39 | 						flag1=1;
 40 | 						for(i=0;i<n;i++)
 41 | 						{
 42 | 							cout<<"Enter the "<<i+1<<" element of the linked list: ";
 43 | 							cin>>arr[i];
 44 | 						}
 45 | 					}
 46 | 					else
 47 | 					{
 48 | 						cout<<"Linked List not created because size provided exceeds the max size\n";
 49 | 					}
 50 | 				}
 51 | 				else
 52 | 				{
 53 | 					cout<<"Linked List is already created!!";
 54 | 				}
 55 | 				break;
 56 | 			case 2:
 57 | 				if(flag1==0)
 58 | 				{
 59 | 					cout<<"Linked List not created\n";
 60 | 				}
 61 | 				else if(n==max)
 62 | 				{
 63 | 					cout<<"Linked list is full and Insertion is not possible";
 64 | 				}
 65 | 				else
 66 | 				{
 67 | 					cout<<"Insertion at the first index"<<endl;
 68 | 					for(i=n-1;i>=0;i--)
 69 | 					{
 70 | 						arr[i+1]=arr[i];
 71 | 					}
 72 | 					cout<<"Enter the element you want to insert: ";
 73 | 					cin>>el;
 74 | 					arr[0]=el;
 75 | 					n++;
 76 | 				}
 77 | 				break;
 78 | 			case 3:
 79 | 				if(flag1==0)
 80 | 				{
 81 | 					cout<<"Linked List not created\n";
 82 | 				}
 83 | 				else if(n==max)
 84 | 				{
 85 | 					cout<<"Linked list is full and Insertion is not possible";
 86 | 				}
 87 | 				else
 88 | 				{
 89 | 					cout<<"Insertion at the Last index"<<endl;
 90 | 					cout<<"Enter the element you want to insert: ";
 91 | 					cin>>el;
 92 | 					arr[n]=el;
 93 | 					n++;
 94 | 				}
 95 | 				break;
 96 | 			case 4:
 97 | 				if(flag1==0)
 98 | 				{
 99 | 					cout<<"Linked List not created\n";
100 | 				}
101 | 				else if(n==max)
102 | 				{
103 | 					cout<<"Linked list is full and Insertion is not possible";
104 | 				}
105 | 				else
106 | 				{
107 | 					cout<<"Insertion at the any index"<<endl;
108 | 					cout<<"Enter the position where you want to insert the value: ";
109 | 					cin>>pos;
110 | 					pos=pos-1;
111 | 					if(pos<0)
112 | 					{
113 | 						cout<<"Under Flow"<<endl;
114 | 					}
115 | 					if(pos>=max-1)
116 | 					{
117 | 						cout<<"Over Flow"<<endl;
118 | 					}
119 | 					else if(pos>=n)
120 | 					{
121 | 						cout<<"Enter the element you want to insert: ";
122 | 						cin>>el;
123 | 						arr[pos]=el;
124 | 						n=pos+1;
125 | 					}
126 | 					else
127 | 					{
128 | 						for(i=n-1;i>=pos-1;i--)
129 | 						{
130 | 							arr[i+1]=arr[i];
131 | 						}
132 | 						cout<<"Enter the element you want to insert: ";
133 | 						cin>>el;
134 | 						arr[pos]=el;
135 | 						n++;
136 | 					}
137 | 				}
138 | 				break;
139 | 			case 5:
140 | 				if(flag1==0)
141 | 				{
142 | 					cout<<"Linked list is not created"<<endl;
143 | 				}
144 | 				else
145 | 				{
146 | 					for(i=1;i<n;i++)
147 | 					{
148 | 					arr[i-1]=arr[i];
149 | 					}
150 | 					arr[n-1]=0;
151 | 					n--;
152 | 				}
153 | 				break;
154 | 			case 6:
155 | 				if(flag1==0)
156 | 				{
157 | 					cout<<"Linked list is not created"<<endl;
158 | 				}
159 | 				else
160 | 				{
161 | 					arr[n-1]=0;
162 | 					n--;
163 | 				}
164 | 				break;
165 | 			case 7:
166 | 				if(flag1==0)
167 | 				{
168 | 					cout<<"Linked list is not created"<<endl;
169 | 				}
170 | 				else
171 | 				{
172 | 					cout<<"Enter the position of deletion: ";
173 | 					cin>>pos;
174 | 					if(pos<0)
175 | 					{
176 | 						cout<<"Under flow Error! Deletion not possible\n";
177 | 					}
178 | 					else if(pos>n-1)
179 | 					{
180 | 						cout<<"Overflow Error! Deletion not possible";
181 | 					}
182 | 					else
183 | 					{
184 | 						for(i=pos;i<n;i++)
185 | 						{
186 | 							arr[i-1]=arr[i];
187 | 						}
188 | 						arr[n-1]=0;
189 | 						n--;
190 | 					}
191 | 				}
192 | 				break;
193 | 			case 8:
194 | 				if(flag1==0)
195 | 				{
196 | 					cout<<"Linked list not created!"<<endl;
197 | 				}
198 | 				else
199 | 				{
200 | 					cout<<"Linked List Traversal\n\n";
201 | 					for(i=0;i<n;i++)
202 | 					{
203 | 						cout<<"The "<<i+1<<" element of the array is: "<<arr[i]<<endl;
204 | 					}
205 | 				}
206 | 				break;
207 | 			case 9: flag = 1;
208 | 				break;
209 | 			default: cout<<"Wrong Choice entered! Exiting the program"<<endl; flag=1;
210 | 		}
211 | 		cout<<"\n\n";
212 | 	}while(flag==0);
213 | 	cout<<"Thank you for using the program!"<<endl;
214 | }
215 | 


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/Linked List/compare.png:
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https://raw.githubusercontent.com/NishkarshRaj/Data-Structures/9e2d0ec5c2848d5f0baf9c39656264ef694c68c1/Linked List/compare.png


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/Linked List/dll.png:
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https://raw.githubusercontent.com/NishkarshRaj/Data-Structures/9e2d0ec5c2848d5f0baf9c39656264ef694c68c1/Linked List/dll.png


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/Queue/CircularQueueArray.cpp:
--------------------------------------------------------------------------------
  1 | #include<iostream>
  2 | using namespace std;
  3 | int main()
  4 | {
  5 | 	cout<<"Circular Queue Using Arrays"<<endl;
  6 | 	int max,i,front,rear,flag=0,ch,el;
  7 | 	cout<<"Enter the maximum size of the Queue you want: ";
  8 | 	cin>>max;
  9 | 	cout<<"Enter the starting size of the Queue: ";
 10 | 	cin>>rear;
 11 | 	int queue[max];
 12 | 	for(i=0;i<max;i++)
 13 | 	{
 14 | 		queue[i]=0; //signify empty queue~!
 15 | 	}
 16 | 	for(i=0;i<rear;i++)
 17 | 	{
 18 | 		cout<<"Enter the "<<i+1<<" element of the Queue: ";
 19 | 		cin>>queue[i];
 20 | 	}
 21 | 	front=0;
 22 | 	do
 23 | 	{
 24 | 		cout<<"\n\nOption Menu"<<endl;
 25 | 		cout<<"1) Enqueue"<<endl;
 26 | 		cout<<"2) Dequeue"<<endl;
 27 | 		cout<<"3) Traversal"<<endl;
 28 | 		cout<<"4) Exit"<<endl;
 29 | 		cout<<"Enter your choice: ";
 30 | 		cin>>ch;
 31 | 		cout<<"\n";
 32 | 		switch(ch)
 33 | 		{
 34 | 			case 1:
 35 | 				cout<<"Enqueue Operation on Circular Queue\n";
 36 | 				if(front<rear)
 37 | 				{
 38 | 					if(((rear==max)&&(front==0))||rear==front-1)
 39 | 					{
 40 | 						cout<<"No more insertions are possible"<<endl;
 41 | 					}
 42 | 					else if(rear<max)
 43 | 					{
 44 | 						cin>>el;
 45 | 						queue[++rear]=el;
 46 | 					}
 47 | 					else if(front>0)
 48 | 					{
 49 | 						cin>>el;
 50 | 						queue[0]=el;
 51 | 						rear=0;
 52 | 					}
 53 | 				}
 54 | 				else
 55 | 				{
 56 | 					if(rear==front-1)
 57 | 					{
 58 | 						cout<<"No more insertion are possible"<<endl;
 59 | 					}
 60 | 					else
 61 | 					{
 62 | 						cin>>el;
 63 | 						queue[++rear]=el;
 64 | 					}
 65 | 				}
 66 | 				break;
 67 | 			case 2:
 68 | 				cout<<"Dequeue Operation on Circular Queue"<<endl;
 69 | 				if(front==rear)
 70 | 				{
 71 | 					cout<<"Deletion is not possible"<<endl;
 72 | 				}
 73 | 				else if(front<rear)
 74 | 				{
 75 | 					queue[front]=0;
 76 | 					front=front+1;
 77 | 				}
 78 | 				else if(rear<front)
 79 | 				{
 80 | 					if(front==max-1)
 81 | 					{
 82 | 						queue[front]=0;
 83 | 						front=0;
 84 | 					}
 85 | 					else
 86 | 					{
 87 | 						queue[front]=0;
 88 | 						front=front+1;
 89 | 					}
 90 | 				}
 91 | 				break;
 92 | 			case 3:
 93 | 				cout<<"Traversal of Circular Queue"<<endl;
 94 | 				cout<<"Front: "<<front<<endl;
 95 | 				cout<<"Rear: "<<rear<<endl;
 96 | 				cout<<"Max: "<<max<<endl;
 97 | 				if(front<=rear)
 98 | 				{
 99 | 					for(i=front;i<rear;i++)
100 | 					{
101 | 						cout<<queue[i]<<"\t";
102 | 					}
103 | 					cout<<"\n";
104 | 				}
105 | 				else
106 | 				{
107 | 					for(i=0;i<=rear;i++)
108 | 					{
109 | 						cout<<queue[i]<<"\t";
110 | 					}
111 | 					for(i=front;i<max;i++)
112 | 					{
113 | 						cout<<queue[i]<<"\t";
114 | 					}
115 | 					cout<<"\n";
116 | 				}
117 | 				break;
118 | 			case 4:
119 | 				flag=1;
120 | 				break;
121 | 			default: cout<<"Wrong choice entered! Exiting the program"<<endl; flag=1;
122 | 		}
123 | 	}while(flag==0);
124 | 	cout<<"Thankyou for using this program"<<endl;
125 | }
126 | 


--------------------------------------------------------------------------------
/Queue/Circular_Queue_LinkedList.cpp:
--------------------------------------------------------------------------------
  1 | #include<iostream>
  2 | using namespace std;
  3 | class Queue
  4 | {
  5 | 	public:
  6 | 	int key;
  7 | 	Queue *next;
  8 | 	void insert()
  9 | 	{
 10 | 		cin>>key;
 11 | 	}
 12 | 	void show()
 13 | 	{
 14 | 		cout<<key;
 15 | 	}
 16 | };
 17 | int main()
 18 | {
 19 | 	Queue *node,*ptr,*front=NULL,*rear=NULL;
 20 | 	int flag=0,ch,count=0,travel;
 21 | 	cout<<"Circular Queue";
 22 | 	do
 23 | 	{
 24 | 		cout<<"\n\n";
 25 | 		cout<<"Option Menu"<<endl;
 26 | 		cout<<"1) Creation of Circular Queue"<<endl;
 27 | 		cout<<"2) Enqueue"<<endl;
 28 | 		cout<<"3) Dequeue"<<endl;
 29 | 		cout<<"4) Traversal"<<endl;
 30 | 		cout<<"5) Exit Program"<<endl;
 31 | 		cout<<"Enter your choice: ";
 32 | 		cin>>ch;
 33 | 		cout<<"\n";
 34 | 		switch(ch)
 35 | 		{
 36 | 			case 1:
 37 | 				if(front==NULL)
 38 | 				{
 39 | 					cout<<"Creation of Circular Queue"<<endl;
 40 | 					node = new Queue;
 41 | 					node->insert();
 42 | 					front=node;
 43 | 					rear=node;
 44 | 					rear->next=front;
 45 | 					count++;
 46 | 				}
 47 | 				else
 48 | 				{
 49 | 					cout<<"Circular Queue is already created!!"<<endl;
 50 | 				}
 51 | 				break;
 52 | 			case 2:
 53 | 				if(front!=NULL)
 54 | 				{
 55 | 					//insertion at last!!!
 56 | 					cout<<"Enqueue => Insertion at Last"<<endl;
 57 | 					node = new Queue;
 58 | 					node->insert();
 59 | 					rear->next=node;
 60 | 					node->next=front;
 61 | 					rear=node;
 62 | 					count++;
 63 | 				}
 64 | 				else
 65 | 				{
 66 | 					cout<<"Before Insertion! Please create a Circular Queue!!\n";
 67 | 				}
 68 | 				break;
 69 | 			case 3:
 70 | 				if(front!=NULL)
 71 | 				{
 72 | 					cout<<"Dequeue operation"<<endl;
 73 | 					ptr=front;
 74 | 					front=ptr->next;
 75 | 					rear->next=front;
 76 | 					delete ptr;
 77 | 					count--;
 78 | 				}
 79 | 				else
 80 | 				{
 81 | 					cout<<"Cannot Dequeue"<<endl;
 82 | 				}
 83 | 				break;
 84 | 			case 4:
 85 | 				if(front!=NULL)
 86 | 				{
 87 | 					travel=count;
 88 | 					cout<<"Traversal of Circular Queue\n\n";
 89 | 					ptr=front;
 90 | 					while(travel--)
 91 | 					{
 92 | 						ptr->show();
 93 | 						ptr=ptr->next; 
 94 | 						cout<<"\t";
 95 | 					}
 96 | 				}
 97 | 				else
 98 | 				{
 99 | 					cout<<"Cannot traverse Queue because it is either empty or not created yet!!"<<endl;
100 | 				}
101 | 				break;
102 | 			case 5:
103 | 				flag=1;
104 | 				break;
105 | 			default: cout<<"Wrong choice entered!! Exiting the code"<<endl; flag=1;
106 | 		}
107 | 	}while(flag==0);
108 | 	cout<<"Thankyou for using this program"<<endl;
109 | }
110 | 


--------------------------------------------------------------------------------
/Queue/Queue_Array.cpp:
--------------------------------------------------------------------------------
  1 | #include<iostream>
  2 | using namespace std;
  3 | int main()
  4 | {
  5 | 	int max,front=-1,rear=-1,i,flag=0,ch,n;
  6 | 	cout<<"General Queue Implementation using Arrays"<<endl;
  7 | 	cout<<"Enter the maximum size of the Queue you want: ";
  8 | 	cin>>max;
  9 | 	int que[max];
 10 | 	for(i=0;i<max;i++)
 11 | 	{
 12 | 		que[i]=0;
 13 | 	}
 14 | 	do
 15 | 	{
 16 | 		cout<<"\n\n";
 17 | 		cout<<"Option Menu"<<endl;
 18 | 		cout<<"1) Creation of Queue"<<endl;
 19 | 		cout<<"2) Enqueue"<<endl;
 20 | 		cout<<"3) Deque"<<endl;
 21 | 		cout<<"4) Peek"<<endl;
 22 | 		cout<<"5) Traversal"<<endl;
 23 | 		cout<<"6) Exit the program"<<endl;
 24 | 		cout<<"Enter your choice: ";
 25 | 		cin>>ch;
 26 | 		cout<<"\n\n";
 27 | 		switch(ch)
 28 | 		{
 29 | 			case 1:
 30 | 				if(front==(-1))
 31 | 				{
 32 | 					cout<<"Creation of Queue"<<endl;
 33 | 					cout<<"Enter the number of elements you want in the queue: ";
 34 | 					cin>>n;
 35 | 					if((n<=max)&&(n>0))
 36 | 					{
 37 | 						for(i=0;i<n;i++)
 38 | 						{
 39 | 							cout<<"Enter the "<<i+1<<" element of the Queue: "<<endl;
 40 | 							cin>>que[i];
 41 | 						}
 42 | 						front=0;
 43 | 						rear=n-1;
 44 | 					}
 45 | 					else if(n>max)
 46 | 					{
 47 | 						cout<<"Overflow Error!!"<<endl;
 48 | 					}
 49 | 					else
 50 | 					{
 51 | 						cout<<"Error Encountered! Insertion not possible!"<<endl;
 52 | 					}
 53 | 				}
 54 | 				else
 55 | 				{
 56 | 					cout<<"Queue is already created!"<<endl;
 57 | 				}
 58 | 				break;
 59 | 			case 2:
 60 | 				if(front==(-1))
 61 | 				{
 62 | 					cout<<"Queue is not not created!!!";
 63 | 				}
 64 | 				else
 65 | 				{
 66 | 					cout<<"Enqueue => Insertion at last"<<endl;
 67 | 					if(n == max)
 68 | 					{
 69 | 						cout<<"Queue is full! No insertion possible"<<endl;
 70 | 					}
 71 | 					else if(n<max)
 72 | 					{
 73 | 						cout<<"Enter the element you want to insert: ";
 74 | 						cin>>que[n];
 75 | 						n++;
 76 | 						rear=n-1;
 77 | 					}
 78 | 				}
 79 | 				break;
 80 | 			case 3:
 81 | 				if(front==(-1))
 82 | 				{
 83 | 					cout<<"Queue is not created"<<endl;
 84 | 				}
 85 | 				else
 86 | 				{
 87 | 					cout<<"Dequeue Operation => Deletion at beginning"<<endl;
 88 | 					if(n==0)
 89 | 					{
 90 | 						cout<<"Queue is empty! No deletion possible"<<endl;
 91 | 					}
 92 | 					else
 93 | 					{
 94 | 						for(i=0;i<n-1;i++)
 95 | 						{
 96 | 							que[i]=que[i+1];
 97 | 						}
 98 | 						que[n-1]=0;
 99 | 						n--;
100 | 						rear=n-1;
101 | 					}
102 | 				}	
103 | 				break;
104 | 			case 4:
105 | 				if(front==(-1))
106 | 				{
107 | 					cout<<"Queue is not created"<<endl;
108 | 				}
109 | 				else
110 | 				{
111 | 					if(n==0)
112 | 					{
113 | 						cout<<"Queue is empty! Nothing to peek"<<endl;
114 | 					}
115 | 					else
116 | 					{
117 | 						cout<<que[0];
118 | 					}
119 | 				}
120 | 				break;
121 | 			case 5:
122 | 				if(front==(-1))
123 | 				{
124 | 					cout<<"Queue is not created"<<endl;
125 | 				}
126 | 				else
127 | 				{
128 | 					cout<<"Traversal of the Queue"<<endl;
129 | 					for(i=0;i<n;i++)
130 | 					{
131 | 						cout<<i+1<<" Element of the queue is: "<<que[i]<<endl;
132 | 					}
133 | 				}
134 | 				break;
135 | 			case 6:
136 | 				flag = 1;
137 | 			 	break;
138 | 			default: cout<<"Wrong Value inserted"<<endl;
139 | 			flag=1;
140 | 		}
141 | 	}while(flag!=1);
142 | 	cout<<"Thank you for using this code!";
143 | }
144 | 


--------------------------------------------------------------------------------
/Queue/Queue_LinkedList.cpp:
--------------------------------------------------------------------------------
  1 | #include<iostream>
  2 | using namespace std;
  3 | class linkedlist
  4 | {
  5 | 	public:
  6 | 		int key;
  7 | 		char value;
  8 | 		string name;
  9 | 		linkedlist *next;
 10 | 		linkedlist()
 11 | 		{
 12 | 			key=0;
 13 | 			value='a';
 14 | 			name="Name";
 15 | 		}
 16 | 		void insertion()
 17 | 		{
 18 | 			cout<<"Enter the Key value of Link: ";
 19 | 			cin>>key;
 20 | 			cout<<"Enter the Character value of the Link: ";
 21 | 			cin>>value;
 22 | 			cout<<"Enter the name of the Link: ";
 23 | 			cin.ignore(); //This is used because of switching from normal data type to string the first switch does not count because of linefeed
 24 | 			getline(cin,name);
 25 | 		}
 26 | 		void display()
 27 | 		{
 28 | 			cout<<"Key value of the Link is: "<<key<<endl;
 29 | 			cout<<"Value of the Link is: "<<value<<endl;
 30 | 			cout<<"Name of the Link is: "<<name<<endl;
 31 | 		}
 32 | };
 33 | int main()
 34 | {
 35 | 	linkedlist *node,*ptr,*front,*p,*rear;
 36 | 	int flag=0,flag1=0,ch,count=0,travel,pos,d,max; //count counts the total number of links created till now
 37 | 	cout<<"Queue (FIFO) Application Using the Linked List Structure"<<endl;
 38 | 	do
 39 | 	{
 40 | 		cout<<"Option Menu"<<endl;
 41 | 		cout<<"1) Creation of Queue"<<endl;
 42 | 		cout<<"2) Enqueue"<<endl;
 43 | 		cout<<"3) Dequeue"<<endl;
 44 | 		cout<<"4) IsFull"<<endl;
 45 | 		cout<<"5) IsEmpty"<<endl;
 46 | 		cout<<"6) Peek"<<endl;
 47 | 		cout<<"7) Traversal of Queue"<<endl;
 48 | 		cout<<"8) Exit the program"<<endl;
 49 | 		cout<<"Enter your choice: ";
 50 | 		cin>>ch;
 51 | 		cout<<"\n\n";
 52 | 		switch(ch)
 53 | 		{
 54 | 			case 1:
 55 | 				if(flag1!=0)
 56 | 				{
 57 | 					cout<<"Linked List already created!"<<endl;
 58 | 				}
 59 | 				else
 60 | 				{
 61 | 					cout<<"Creation of Queue\n\n";
 62 | 					cout<<"Create the first node of the Linked List\n";
 63 | 					flag1 = 1;
 64 | 					node = new linkedlist;
 65 | 					node->insertion();
 66 | 					node->next=NULL;
 67 | 					front=node;
 68 | 					rear=node;
 69 | 					count++;
 70 | 					cout<<"\n\nQueue Is created!!!"<<endl;
 71 | 					cout<<"Enter the Max Size of Queue: ";
 72 | 					cin>>max;
 73 | 				}
 74 | 				break;
 75 | 			case 2:
 76 | 				if(flag1==0)
 77 | 				{
 78 | 					cout<<"Queue is not created"<<endl;
 79 | 				}
 80 | 				else
 81 | 				{
 82 | 					cout<<"Insertion of link at the end of the list"<<endl;
 83 | 					node = new linkedlist;
 84 | 					node->insertion();
 85 | 					node->next=NULL;
 86 | 					rear->next = node;
 87 | 					count++;
 88 | 				}
 89 | 				break;
 90 | 			case 3:
 91 | 				if(flag1==0)
 92 | 				{
 93 | 					cout<<"Queue is not created"<<endl;
 94 | 				}
 95 | 				else
 96 | 				{
 97 | 					cout<<"Deletion from beginning"<<endl;
 98 | 					ptr = front;
 99 | 					front = ptr->next;
100 | 					delete ptr;
101 | 					count--;
102 | 				}
103 | 				break;
104 | 			case 4:
105 | 				if(flag1==0)
106 | 				{
107 | 					cout<<"Queue not created!!";
108 | 				}
109 | 				else
110 | 				{
111 | 					cout<<"Check for Is Full for Queue"<<endl;
112 | 					if(count==max)
113 | 					{
114 | 						cout<<"Queue is Full"<<endl;
115 | 					}
116 | 					else
117 | 					{
118 | 						cout<<"Queue is not full"<<endl;
119 | 					}
120 | 				}
121 | 				break;
122 | 			case 5:
123 | 				if(flag1 == 0)
124 | 				{
125 | 					cout<<"Queue is not created"<<endl;
126 | 				}
127 | 				else
128 | 				{
129 | 					cout<<"Check for Queue is Empty?"<<endl;
130 | 					if(count==0)
131 | 					{
132 | 						cout<<"Queue is empty"<<endl;
133 | 					}
134 | 					else
135 | 					{
136 | 						cout<<"Queue is not empty"<<endl;
137 | 					}
138 | 				}
139 | 				break;
140 | 			case 6:
141 | 				if(flag1 == 0)
142 | 				{
143 | 					cout<<"Queue is not created\n";
144 | 				}
145 | 				else
146 | 				{
147 | 					cout<<"Displaying the Front of Queue!"<<endl;
148 | 					front->display();
149 | 				}
150 | 				break;
151 | 			case 7: 
152 | 				if(flag1==0)
153 | 				{
154 | 					cout<<"Queue not created!"<<endl;
155 | 				}
156 | 				else
157 | 				{
158 | 					cout<<"Linked List Traversal\n\n";
159 | 					travel=0;
160 | 					for(ptr=front;ptr!=NULL;ptr=ptr->next)
161 | 					{
162 | 						cout<<++travel<<" Link of the List is\n";
163 | 						ptr->display();
164 | 						cout<<"\n";
165 | 					}
166 | 				}
167 | 				break;
168 | 			case 8:
169 | 				flag = 1;
170 | 				break;
171 | 			default: cout<<"Wrong choice Entered!! Exiting program"; flag=1;
172 | 		}
173 | 		cout<<"\n\n";
174 | 	}while(flag!=1);
175 | 	cout<<"\nThank you for using the program"<<endl;
176 | }
177 | 


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/README.md:
--------------------------------------------------------------------------------
 1 | # Data-Structures
 2 | 
 3 | ## Arrays
 4 | [1) General Array Code](https://github.com/NishkarshRaj/Data-Structures/blob/master/Arrays/Arrays.cpp)
 5 | 
 6 | ## Two Dimensional Arrays
 7 | [1) Array Of Strings](https://github.com/NishkarshRaj/Data-Structures/blob/master/2%20Dimensional%20Arrays/ArrayOfString.c)
 8 | 
 9 | [2) Matrix Addition](https://github.com/NishkarshRaj/Data-Structures/blob/master/2%20Dimensional%20Arrays/MatrixAddition.cpp)
10 | 
11 | [3) Matrix Multiplication](https://github.com/NishkarshRaj/Data-Structures/blob/master/2%20Dimensional%20Arrays/MatrixMultiplication.cpp)
12 | 
13 | [4) Sum of Rows](https://github.com/NishkarshRaj/Data-Structures/blob/master/2%20Dimensional%20Arrays/SumOfRows.cpp)
14 | 
15 | [5) Sum of Columns](https://github.com/NishkarshRaj/Data-Structures/blob/master/2%20Dimensional%20Arrays/SumOfColumn.cpp)
16 | 
17 | [6) Sum of All elements](https://github.com/NishkarshRaj/Data-Structures/blob/master/2%20Dimensional%20Arrays/SumOfallElements.cpp)
18 | 
19 | ## Linked List
20 | [1) General Single Link Linked List using Structures](https://github.com/NishkarshRaj/Data-Structures/blob/master/Linked%20List/LinkedList.cpp)
21 | 
22 | [2) Single Link Linked List using Arrays](https://github.com/NishkarshRaj/Data-Structures/blob/master/Linked%20List/LinkedList_Array.cpp)
23 | 
24 | [3) Doubly Linked List using Classes and Objects](https://github.com/NishkarshRaj/Data-Structures/blob/master/Linked%20List/DoublyLinkedList.cpp)
25 | 
26 | ## Stack
27 | [1) Stacks using Linked List](https://github.com/NishkarshRaj/Data-Structures/blob/master/Stack/Stack_LinkedList.cpp)
28 | 
29 | [2) Stacks using Arrays](https://github.com/NishkarshRaj/Data-Structures/blob/master/Stack/Stack_Arrays.cpp)
30 | 
31 | ## Queue
32 | [1) Queues Using Linked List](https://github.com/NishkarshRaj/Data-Structures/blob/master/Queue/Queue_LinkedList.cpp)
33 | 
34 | [2) Queues Using Arrays](https://github.com/NishkarshRaj/Data-Structures/blob/master/Queue/Queue_Array.cpp)
35 | 
36 | [3) Circular Queues using Linked List](https://github.com/NishkarshRaj/Data-Structures/blob/master/Queue/Circular_Queue_LinkedList.cpp)
37 | 
38 | [4) Circular Queues using Arrays](https://github.com/NishkarshRaj/Data-Structures/blob/master/Queue/CircularQueueArray.cpp)
39 | 
40 | ## Trees
41 | [1) Inorder Traversal of Binary Tree](https://github.com/NishkarshRaj/Data-Structures/blob/master/Binary%20Trees/InorderTraversal.cpp)
42 | 
43 | [2) Post Order Traversal of Binary Tree](https://github.com/NishkarshRaj/Data-Structures/blob/master/Binary%20Trees/PostOrderTraversal.cpp)
44 | 
45 | [3) Pre Order Traversal of Binary Tree](https://github.com/NishkarshRaj/Data-Structures/blob/master/Binary%20Trees/PreOrderTraversal.cpp)
46 | 
47 | [4) Breadth First Traversal (Level Order)](https://github.com/NishkarshRaj/Data-Structures/blob/master/Binary%20Trees/BFSTraversal.cpp)
48 | 
49 | [5) Binary Tree General Code](https://github.com/NishkarshRaj/Data-Structures/blob/master/Binary%20Trees/BinaryTrees.cpp)
50 | 
51 | ## How to Contribution
52 | 
53 | [Contribution Guidelines](CONTRIBUTING.md)
54 | 


--------------------------------------------------------------------------------
/Stack/Stack_Arrays.cpp:
--------------------------------------------------------------------------------
  1 | #include<iostream>
  2 | using namespace std;
  3 | int main()
  4 | {
  5 | 	int max,n,i,flag=0,ch,top=-1;
  6 | 	cout<<"Implementing Stacks using Arrays"<<endl;
  7 | 	cout<<"Enter the Max Size of the Array: ";
  8 | 	cin>>max;
  9 | 	int stack[max];
 10 | 	for(i=0;i<max;i++)
 11 | 	{
 12 | 		stack[i]=0;
 13 | 	}
 14 | 	do
 15 | 	{
 16 | 		cout<<"\n\n";
 17 | 		cout<<"Option Menu"<<endl;
 18 | 		cout<<"1) Creation of Stack"<<endl;
 19 | 		cout<<"2) Push"<<endl;
 20 | 		cout<<"3) Pop"<<endl;
 21 | 		cout<<"4) Peek"<<endl;
 22 | 		cout<<"5) Traversal"<<endl;
 23 | 		cout<<"6) Exit"<<endl;
 24 | 		cout<<"Enter your choice: ";
 25 | 		cin>>ch;
 26 | 		cout<<"\n\n";
 27 | 		switch(ch)
 28 | 		{
 29 | 			case 1:
 30 | 				if(top==-1)
 31 | 				{
 32 | 					cout<<"Creation of Stack"<<endl;
 33 | 					cout<<"Enter the number of elements you want: ";
 34 | 					cin>>n;
 35 | 					if(n<0)
 36 | 					{
 37 | 						cout<<"Number of elements cannot be negative"<<endl;
 38 | 					}
 39 | 					else if(n>max)
 40 | 					{
 41 | 						cout<<"Overflow Error"<<endl;
 42 | 					}
 43 | 					else
 44 | 					{
 45 | 						for(i=0;i<n;i++)
 46 | 						{
 47 | 							cout<<"Enter Element: ";
 48 | 							cin>>stack[i];
 49 | 						}
 50 | 						top=n-1;
 51 | 					}
 52 | 				}
 53 | 				else
 54 | 				{
 55 | 					cout<<"Stack is already created!!"<<endl;
 56 | 				}
 57 | 				break;
 58 | 			case 2:
 59 | 				if(top==-1)
 60 | 				{
 61 | 					cout<<"Stack is not created"<<endl;
 62 | 				}
 63 | 				else
 64 | 				{
 65 | 					cout<<"Push => Insertion at top"<<endl;
 66 | 					if(n==max)
 67 | 					{
 68 | 						cout<<"Stack is full and push is not possible"<<endl;
 69 | 					}
 70 | 					else
 71 | 					{
 72 | 						cout<<"Enter element: ";
 73 | 						cin>>stack[n];
 74 | 						n++;
 75 | 						top=n-1;
 76 | 					}
 77 | 				}
 78 | 				break;
 79 | 			case 3:	
 80 | 				if(top==-1)
 81 | 				{
 82 | 					cout<<"Stack is not created!!"<<endl;
 83 | 				}
 84 | 				else
 85 | 				{
 86 | 					if(n==0)
 87 | 					{
 88 | 						cout<<"Stack is empty"<<endl;
 89 | 					}
 90 | 					else if(n==1)
 91 | 					{
 92 | 						stack[n-1]=0;
 93 | 						n--;
 94 | 						top=0;
 95 | 					}
 96 | 					else
 97 | 					{
 98 | 						stack[n-1]=0;
 99 | 						n--;
100 | 						top=n-1;
101 | 					}
102 | 				}
103 | 				break;
104 | 			case 4:
105 | 				if(top==-1)
106 | 				{
107 | 					cout<<"Stack is not created"<<endl;
108 | 				}
109 | 				else
110 | 				{
111 | 					if(n==0)
112 | 					{
113 | 						cout<<"Stack is empty"<<endl;
114 | 					}
115 | 					else
116 | 					{
117 | 						cout<<stack[top];
118 | 					}
119 | 				}
120 | 				break;
121 | 			case 5:
122 | 				if(top==-1)
123 | 				{
124 | 					cout<<"Stack is not created!!"<<endl;	
125 | 				}
126 | 				else if(top==0)
127 | 				{
128 | 					cout<<"Stack is empty"<<endl;
129 | 				}
130 | 				else
131 | 				{
132 | 					cout<<"Traversal of Stack\n"<<endl;
133 | 					for(i=top;i>=0;i--)
134 | 					{
135 | 						cout<<stack[i]<<endl;
136 | 					}
137 | 				}
138 | 				break;
139 | 			case 6:
140 | 				flag=1;
141 | 				break;
142 | 			default: cout<<"Wrong Choice! Exiting the program"<<endl; flag=1; 
143 | 		}
144 | 	}while(flag==0);
145 | }
146 | 


--------------------------------------------------------------------------------
/Stack/Stack_LinkedList.cpp:
--------------------------------------------------------------------------------
  1 | #include<iostream>
  2 | using namespace std;
  3 | class stack
  4 | {
  5 | public:
  6 | int key;
  7 | stack *next;
  8 | void insert()
  9 | {
 10 | 	cout<<"\n\nInsertion of Link"<<endl;
 11 | 	cout<<"Enter the Key value: ";
 12 | 	cin>>key;	
 13 | }	
 14 | void display()
 15 | {
 16 | 	cout<<key<<endl;
 17 | }
 18 | };
 19 | int main()
 20 | {
 21 | 	stack *top,*node,*ptr;
 22 | 	int flag=0,ch,count=0,flag1=0,i,max;
 23 | 	cout<<"Implementing Stack Using Linked List"<<endl;
 24 | 	do
 25 | 	{
 26 | 		cout<<"\n\nOption Menu"<<endl;
 27 | 		cout<<"1) Creation of Stack"<<endl;
 28 | 		cout<<"2) Push"<<endl;
 29 | 		cout<<"3) Pop"<<endl;
 30 | 		cout<<"4) Peek"<<endl;
 31 | 		cout<<"5) IsFull"<<endl;
 32 | 		cout<<"6) IsEmpty"<<endl;
 33 | 		cout<<"7) Traversal"<<endl;
 34 | 		cout<<"8) Exit Program"<<endl;
 35 | 		cout<<"Enter your choice: ";
 36 | 		cin>>ch;
 37 | 		cout<<"\n\n";
 38 | 		switch(ch)
 39 | 		{
 40 | 			case 1:
 41 | 				if(flag1==0)
 42 | 				{
 43 | 					cout<<"Creation of Stack"<<endl;
 44 | 					flag1=1;
 45 | 					node = new stack;
 46 | 					node->insert();
 47 | 					node->next=NULL;
 48 | 					top=node;
 49 | 					count++;
 50 | 					cout<<"\nStack is created!! Enter the maximum size of stack you want: ";
 51 | 					cin>>max;
 52 | 				}
 53 | 				else
 54 | 				{
 55 | 					cout<<"Stack is already created"<<endl;
 56 | 				}
 57 | 				break;
 58 | 			case 2:
 59 | 				if(flag1==0)
 60 | 				{
 61 | 					cout<<"Stack is not created"<<endl;
 62 | 				}
 63 | 				else
 64 | 				{
 65 | 					if(count==max)
 66 | 					{
 67 | 						cout<<"Stack is full! Push is not possible"<<endl;
 68 | 					}
 69 | 					else
 70 | 					{
 71 | 						node = new stack;
 72 | 						node->insert();
 73 | 						node->next=top;
 74 | 						top=node;
 75 | 						count++;
 76 | 					}
 77 | 				}
 78 | 				break;
 79 | 			case 3:
 80 | 				if(flag1==0)
 81 | 				{
 82 | 					cout<<"Stack is not created"<<endl;
 83 | 				}
 84 | 				else
 85 | 				{
 86 | 					if(count==0)
 87 | 					{
 88 | 						cout<<"Stack is empty!! Deletion is not possible"<<endl;
 89 | 					}
 90 | 					else if(count==1)
 91 | 					{
 92 | 						ptr=top;
 93 | 						top=NULL;
 94 | 						delete ptr;
 95 | 						count--;
 96 | 					}
 97 | 					else 
 98 | 					{
 99 | 						ptr=top;
100 | 						top=ptr->next;
101 | 						delete ptr;
102 | 						count--;
103 | 					}
104 | 				}
105 | 				break;
106 | 			case 4:
107 | 				if(flag1==0)
108 | 				{
109 | 					cout<<"Stack is not created!!"<<endl;
110 | 				}
111 | 				else
112 | 				{
113 | 					cout<<"Peek => Displaying the Top"<<endl;
114 | 					if(count==0)
115 | 					{
116 | 						cout<<"Stack is empty"<<endl;
117 | 					}
118 | 					else
119 | 					{
120 | 						top->display();
121 | 					}
122 | 				}
123 | 				break;
124 | 			case 5:
125 | 				if(flag1==0)
126 | 				{
127 | 					cout<<"Stack is not created"<<endl;
128 | 				}
129 | 				else
130 | 				{
131 | 					if(count==max)
132 | 					{
133 | 						cout<<"Stack is full"<<endl;
134 | 					}
135 | 					else
136 | 					{
137 | 						cout<<"Stack is not full"<<endl;
138 | 					}
139 | 				}
140 | 				break;
141 | 			case 6:
142 | 				if(flag1==0)
143 | 				{
144 | 					cout<<"Stack is not created"<<endl;
145 | 				}
146 | 				else
147 | 				{
148 | 					if(count==0)
149 | 					{
150 | 						cout<<"Stack is empty"<<endl;
151 | 					}
152 | 					else
153 | 					{
154 | 						cout<<"Stack is not empty"<<endl;
155 | 					}
156 | 				}
157 | 				break;
158 | 			case 7:
159 | 				if(flag1==0)
160 | 				{
161 | 					cout<<"Stack is not created"<<endl;
162 | 				}
163 | 				else
164 | 				{
165 | 					cout<<"Stack Traversal"<<endl;
166 | 					i=0;
167 | 					for(ptr=top;ptr!=NULL;ptr=ptr->next)
168 | 					{
169 | 						cout<<"Displaying the "<<++i<<" Link of the Stack: ";
170 | 						ptr->display();
171 | 					}
172 | 				}
173 | 				break;
174 | 			case 8:
175 | 				flag=1;
176 | 				break;
177 | 			default: cout<<"Wrong Choice entered! Exiting the code"<<endl; flag=1;
178 | 		}
179 | 		cout<<"\n\n";
180 | 	}while(flag==0);
181 | 	cout<<"Thanks for using the code"<<endl;
182 | }
183 | 


--------------------------------------------------------------------------------