EchoClient.c

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

#define ERROR -1
#define BUFFER 1024

int main(int argc,char **argv){
	struct sockaddr_in remote_server;
	int sock;
	char input[BUFFER], output[BUFFER];
	int len;
	if((sock = socket(AF_INET,SOCK_STREAM,0))== ERROR){
		perror("socket: ");
		exit(-1);
	}
	remote_server.sin_family = AF_INET;
	remote_server.sin_port = htons(atoi(argv[2]));
	remote_server.sin_addr.s_addr = inet_addr(argv[1]);
	bzero(&remote_server.sin_zero,0);
	
	if(connect(sock,(struct sockaddr *)&remote_server,sizeof(struct sockaddr_in))==ERROR){
		perror("connect ");
		exit(-1);
	}	
	
	while(1){
	
	fgets(input,BUFFER,stdin);	
	send(sock,input,strlen(input),0);
	
	len = recv(sock,output,BUFFER,0);
	output[len]='\0';
	printf("%s\n",output);
	}
close(sock);	
}