socket server programming

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

void error(const char *msg)
{
perror(msg);
exit(1);
}

int main(int argc, char *argv[])
{
if(argc < 2){
fprintf(stderr, "Port No not provided. Program terminated\n");
exit(1);
}


int sockfd, newsockfd, portno, n;
char buffer[255];

struct sockaddr_in serv_addr, cli_addr;
socklen_t clilen;

sockfd = socket(AF_INET, SOCK_STREAM, 0);
if(sockfd < 0)
{
error("Error opening Socket.");
}

bzero((char *) &serv_addr, sizeof(serv_addr));
portno = atoi(argv[1]);

serv_addr.sin_family = AF_INET;
serv_addr.sin_addr.s_addr = INADDR_ANY;
serv_addr.sin_port = htons(portno);

if(bind(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0)
error("Binding Failed.");

listen(sockfd, 5);
clilen = sizeof(cli_addr);

newsockfd = accept(sockfd, (struct sockaddr *) &cli_addr, &clilen);

if(newsockfd < 0)
error("Error on Accpt");

while(1)
{
bzero(buffer, 256);
n = read(newsockfd, buffer, 255);
if(n < 0)
error("Error on reading.");
printf("Client :%s\n", buffer);
bzero(buffer, 255);
fgets(buffer, 255, stdin);

n = write(newsockfd, buffer, strlen(buffer));
if(n < 0)
error("Error on Writing\n");

int i = strncmp("Bye", buffer, 3);
if(i == 0)
break;

}

close(newsockfd);
close(sockfd);
return 0;

}

// compile : gcc -o server server.c

// server 9999