socket client programming

/*
 * filename server_ipaddress portno
 *
 * argv[0] filename
 * argv[1] server_ipaddress]
 * argv[2] portno */

#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(0);
}

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){
fprintf(stderr, "Error, no such host");
}

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:");

while(1){
bzero(buffer, 255);
fgets(buffer, 255, stdin);
n = write(sockfd, buffer, strlen(buffer));
if(n < 0)
error("Error on writing");
bzero(buffer, 255);
n = read(sockfd, buffer, 255);
if(n < 0)
error("Error on reading.");
printf("Server: %s", buffer);

int i = strncmp("bye", buffer, 3);
if (i == 0)
break;
}
close(sockfd);
return 0;

}

// compile: gcc -o client client.c

// client 127.0.0.1 or IP 9999