client.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>

void error(const char * msg){
	perror(msg);
	exit(1);
}
int main(int argc, char *argv[]){
	int sockfd, portno, n;
	struct sockaddr_in serv_addr;
	struct hostent * server;
	char buffer[256];
	if(argc < 3){
		fprintf(stderr, "Usage %s hostname port\n", argv[0]);
		exit(0);
	}
	portno = atoi(argv[2]);
	sockfd = socket(AF_INET, SOCK_STREAM, 0);
	if(sockfd < 0) error("ERROR opening socket");
	server = gethostbyname(argv[1]);
	if(server == NULL) error("No such host\n");
	bzero((char *) &serv_addr, sizeof(serv_addr) );
	serv_addr.sin_family = AF_INET;
	bcopy((char *) server->h_addr, (char *) &serv_addr.sin_addr.s_addr, server->h_length);
	serv_addr.sin_port = htons(portno);
	if(connect(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0){
		error("Connection failed\n");	
	}
	while(1){
		bzero(buffer, 255);
		fgets(buffer, 255, stdin);
		n = write(sockfd, buffer, strlen(buffer));
		if(n < 0) error("Error on writing\n");
		bzero(buffer, 255);
		n = read(sockfd, buffer, 255);
		if(n < 0) error("Error on reading\n");
		printf("Server: %s", buffer);
		if(strncmp("bye", buffer, 3) == 0){
			break;
		}
	}
	close(sockfd);
	return 0;
}