└── TCP Server
    └── main.cpp


/TCP Server/main.cpp:
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  1 | #include<iostream>
  2 | #include<string.h>
  3 | #include<winsock2.h>
  4 | #include<ws2tcpip.h>
  5 | // #define _WINSOCK_DEPRECATED_NO_WARNINGS
  6 | // #define _CRT_SECURE_NO_WARNINGS
  7 | // #define NI_MAXHOST 1025
  8 | 
  9 | 
 10 | #pragma comment(lib, "ws2_32.lib")
 11 | 
 12 | using namespace std;
 13 | 
 14 | int main() {
 15 |     // Initialize Winsock
 16 |     WSADATA wsData;
 17 |     WORD ver = MAKEWORD(2, 2);
 18 | 
 19 |     int wsOk = WSAStartup(ver, &wsData);
 20 |     if (wsOk != 0) {
 21 | 
 22 |         cerr << "Cannot initialize winsock. Quitting !!" << endl;
 23 |         return 1;
 24 |     }
 25 | 
 26 |     //create a socket
 27 |     SOCKET listening = socket(AF_INET, SOCK_STREAM, 0);
 28 | 
 29 |     if (listening == INVALID_SOCKET) {
 30 | 
 31 |         cerr << "Cannot create a socket. Quitting !!" << endl;
 32 |         return 1;
 33 |     }
 34 | 
 35 |     //bind the socket to an ip address and port
 36 | 
 37 |     sockaddr_in hint;
 38 |     hint.sin_family = AF_INET;
 39 |     hint.sin_port = htons(54000);
 40 |     hint.sin_addr.S_un.S_addr = INADDR_ANY;  //could also use inet_pton
 41 |     bind(listening, (sockaddr*)&hint, sizeof(hint));
 42 | 
 43 |     //tell winsock the socket is for listening
 44 | 
 45 |     listen(listening, SOMAXCONN);
 46 | 
 47 |     //wait for a connection
 48 | 
 49 |     sockaddr_in client;
 50 |     int clientsize = sizeof(client);
 51 |     SOCKET clientsocket = accept(listening, (sockaddr*)&client, &clientsize);
 52 |     // if (clientsocket == INVALID_SOCKET) //Do something 
 53 |     // {
 54 | 
 55 |     // }
 56 |     char host[NI_MAXHOST]; // client remote name
 57 |     char service[NI_MAXSERV]; // servuce(i.e port ) the client is connect on  
 58 | 
 59 |     ZeroMemory(host, NI_MAXHOST); // same as  memset(host, 0, NI_MAXHOST);
 60 |     ZeroMemory(service, NI_MAXSERV);
 61 |     if (getnameinfo((sockaddr*)&client, sizeof(client), host, NI_MAXHOST, service, NI_MAXSERV, 0) == 0) {
 62 |         cout << host << "Connected on port " << service << endl;
 63 |     }
 64 |     else {
 65 | 
 66 |         inet_ntop(AF_INET, &client.sin_addr, host, NI_MAXHOST);
 67 |         cout << host << "Connected on port " <<
 68 |             ntohs(client.sin_port) << endl; // ntohs = network to host short
 69 |     }
 70 | 
 71 |     //close listening socket
 72 |     closesocket(listening);
 73 | 
 74 |     //while loop: accept and echo message back to client
 75 |     char buf[4096];
 76 |     while (true) {
 77 |         ZeroMemory(buf, 4096);
 78 |         //wait for client to send data.
 79 | 
 80 |         int bytesReceived = recv(clientsocket, buf, 4096, 0);
 81 |         if (bytesReceived == SOCKET_ERROR)
 82 |         {
 83 |             cerr << " Error in recv(). Quitting " << endl;
 84 |             break;
 85 |         }
 86 |         if (bytesReceived == 0) {
 87 |             cout << " Client Disconnected. " << endl;
 88 |             break;
 89 |         }
 90 |         send(clientsocket, buf, bytesReceived + 1, 0);
 91 | 
 92 | 
 93 |         //echo message back to the client 
 94 |     }
 95 | 
 96 |     //close the socket
 97 |       
 98 |     closesocket(clientsocket);
 99 | 
100 |     //Cleanup winsock
101 | 
102 |     WSACleanup();
103 | }


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