echoClient.c

#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>
#include <arpa/inet.h>

#define MAXLINE 4096
#define SERV_PORT 3000 

int
main(int argc, char **argv)
{
 int sockfd;
 struct sockaddr_in servaddr;
 char sendline[MAXLINE], recvline[MAXLINE];


 if (argc !=2) {
  perror("Usage: TCPClient <IP address of the server");
  exit(1);
 }


 if ((sockfd = socket (AF_INET, SOCK_STREAM, 0)) <0) {
  perror("Problem in creating the socket");
  exit(2);
 }

 memset(&servaddr, 0, sizeof(servaddr));
 servaddr.sin_family = AF_INET;
 servaddr.sin_addr.s_addr= inet_addr(argv[1]);
 servaddr.sin_port =  htons(SERV_PORT); 


 if (connect(sockfd, (struct sockaddr *) &servaddr, sizeof(servaddr))<0) {
  perror("Problem in connecting to the server");
  exit(3);
 }

 while (fgets(sendline, MAXLINE, stdin) != NULL) {

  send(sockfd, sendline, strlen(sendline), 0);

  if (recv(sockfd, recvline, MAXLINE,0) == 0){
   perror("The server terminated prematurely");
   exit(4);
  }
  printf("%s", "String received from the server: ");
  fputs(recvline, stdout);
 }

 exit(0);
}