├── README.md
├── client.c
└── server.c


/README.md:
--------------------------------------------------------------------------------
 1 | # UDP-Client-Server-implementation-in-C
 2 | 
 3 | A simple implementation of the UDP (User Datagram Protocol) client-server program in the C programming language. Here, both the client and server are going to communicate with each other by exchanging messages.
 4 | 
 5 | Blog Post: [UDP Client-Server Implementation in C](https://idiotdeveloper.com/udp-client-server-implementation-in-c/) <br/>
 6 | YouTube Video: [UDP Client Server implementation in C | Socket Programming ](https://youtu.be/1Tdr9LcJt0I)
 7 | 
 8 | # Exceute the program
 9 | Compile the program
10 | <pre>
11 | $ gcc server.c -o server
12 | $ gcc client.c -o client
13 | </pre>
14 | 
15 | Run the program
16 | <pre>
17 | $ ./server 4455
18 | $ ./client 4455
19 | </pre>
20 | 


--------------------------------------------------------------------------------
/client.c:
--------------------------------------------------------------------------------
 1 | #include <stdio.h>
 2 | #include <stdlib.h>
 3 | #include <string.h>
 4 | #include <sys/socket.h>
 5 | #include <sys/types.h>
 6 | #include <netinet/in.h>
 7 | #include <arpa/inet.h>
 8 | 
 9 | int main(int argc, char **argv){
10 | 
11 |   if (argc != 2) {
12 |     printf("Usage: %s <port>\n", argv[0]);
13 |     exit(0);
14 |   }
15 | 
16 |   char *ip = "127.0.0.1";
17 |   int port = atoi(argv[1]);
18 | 
19 |   int sockfd;
20 |   struct sockaddr_in addr;
21 |   char buffer[1024];
22 |   socklen_t addr_size;
23 | 
24 |   sockfd = socket(AF_INET, SOCK_DGRAM, 0);
25 |   memset(&addr, '\0', sizeof(addr));
26 |   addr.sin_family = AF_INET;
27 |   addr.sin_port = htons(port);
28 |   addr.sin_addr.s_addr = inet_addr(ip);
29 | 
30 |   bzero(buffer, 1024);
31 |   strcpy(buffer, "Hello, World!");
32 |   sendto(sockfd, buffer, 1024, 0, (struct sockaddr*)&addr, sizeof(addr));
33 |   printf("[+]Data send: %s\n", buffer);
34 | 
35 |   bzero(buffer, 1024);
36 |   addr_size = sizeof(addr);
37 |   recvfrom(sockfd, buffer, 1024, 0, (struct sockaddr*)&addr, &addr_size);
38 |   printf("[+]Data recv: %s\n", buffer);
39 | 
40 |   return 0;
41 | }
42 | 


--------------------------------------------------------------------------------
/server.c:
--------------------------------------------------------------------------------
 1 | #include <stdio.h>
 2 | #include <stdlib.h>
 3 | #include <string.h>
 4 | #include <sys/socket.h>
 5 | #include <sys/types.h>
 6 | #include <netinet/in.h>
 7 | #include <arpa/inet.h>
 8 | 
 9 | int main(int argc, char **argv){
10 | 
11 |   if (argc != 2){
12 |     printf("Usage: %s <port>\n", argv[0]);
13 |     exit(0);
14 |   }
15 | 
16 |   char *ip = "127.0.0.1";
17 |   int port = atoi(argv[1]);
18 | 
19 |   int sockfd;
20 |   struct sockaddr_in server_addr, client_addr;
21 |   char buffer[1024];
22 |   socklen_t addr_size;
23 |   int n;
24 | 
25 |   sockfd = socket(AF_INET, SOCK_DGRAM, 0);
26 |   if (sockfd < 0){
27 |     perror("[-]socket error");
28 |     exit(1);
29 |   }
30 | 
31 |   memset(&server_addr, '\0', sizeof(server_addr));
32 |   server_addr.sin_family = AF_INET;
33 |   server_addr.sin_port = htons(port);
34 |   server_addr.sin_addr.s_addr = inet_addr(ip);
35 | 
36 |   n = bind(sockfd, (struct sockaddr*)&server_addr, sizeof(server_addr));
37 |   if (n < 0) {
38 |     perror("[-]bind error");
39 |     exit(1);
40 |   }
41 | 
42 |   bzero(buffer, 1024);
43 |   addr_size = sizeof(client_addr);
44 |   recvfrom(sockfd, buffer, 1024, 0, (struct sockaddr*)&client_addr, &addr_size);
45 |   printf("[+]Data recv: %s\n", buffer);
46 | 
47 |   bzero(buffer, 1024);
48 |   strcpy(buffer, "Welcome to the UDP Server.");
49 |   sendto(sockfd, buffer, 1024, 0, (struct sockaddr*)&client_addr, sizeof(client_addr));
50 |   printf("[+]Data send: %s\n", buffer);
51 | 
52 |   return 0;
53 | }
54 | 


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