Socket Programming In C (TCP)

     
    #include"stdio.h"
    #include"stdlib.h"
    #include"sys/types.h"
    #include"sys/socket.h"
    #include"string.h"
    #include"netinet/in.h"

    #define PORT 4444
    #define BUF_SIZE 20

    void main() {
     struct sockaddr_in addr, cl_addr;
     int sockfd, len, ret, newsockfd;
     char buffer[BUF_SIZE];
     
     sockfd = socket(AF_INET, SOCK_STREAM, 0);
     if (sockfd < 0) {
      printf("Error creating socket!\n");
      exit(1);
     }
     printf("Socket created...\n");
     
     memset(&addr, 0, sizeof(addr));
     addr.sin_family = AF_INET;
     addr.sin_addr.s_addr = INADDR_ANY;
     addr.sin_port = PORT;
     
     ret = bind(sockfd, (struct sockaddr *) &addr, sizeof(addr));
     if (ret < 0) {
      printf("Error binding!\n");
      exit(1);
     }
     printf("Binding done...\n");

     printf("Waiting for a connection...\n");
     listen(sockfd, 5);

     len = sizeof(cl_addr);
     newsockfd = accept(sockfd, (struct sockaddr *) &cl_addr, &len);
     if (newsockfd < 0) {
      printf("Error accepting connection!\n");
      exit(1);
     }
     printf("Connection accepted...\n"); 

     memset(buffer, 0, BUF_SIZE);
     ret = recv(newsockfd, buffer, BUF_SIZE, 0);
     if(ret < 0) {
      printf("Error receiving data!\n");  
      exit(1);
     }
     printf("Received data: %s\n", buffer); 
    }

     
    #include"stdio.h"
    #include"stdlib.h"
    #include"sys/types.h"
    #include"sys/socket.h"
    #include"string.h"
    #include"netinet/in.h"

    #define PORT 4444

    void main() {
     struct sockaddr_in addr, cl_addr;
     int sockfd, ret;
     char * buffer="hi there?";
     
     sockfd = socket(AF_INET, SOCK_STREAM, 0);
     if (sockfd < 0) {
      printf("Error creating socket!\n");
      exit(1);
     }
     printf("Socket created...\n");
     
     memset(&addr, 0, sizeof(addr));
     addr.sin_family = AF_INET;
     addr.sin_addr.s_addr = INADDR_ANY;
     addr.sin_port = PORT;   

     ret = connect(sockfd, (struct sockaddr *) &addr, sizeof(addr));
     if (ret < 0) {
      printf("Error connecting to the server!\n");
      exit(1);
     }
     printf("Connected to the server...\n");
     
     ret = send(sockfd, buffer, strlen(buffer), 0);
     if (ret < 0) {
      printf("Error sending data!\n");
      exit(1);
     }
     printf("Sent data: %s\n", buffer);
    }