Concurrent Socket Program

In This Program Many Child Can Chat With Same Server Simultaneously
Server Program
Input : Port Number

#include<stdio.h>
#include<unistd.h>
#include<sys/socket.h>
#include<sys/ipc.h>
#include<netinet/in.h>
#include<stdlib.h>
#include<netdb.h>
#include<string.h>
int main(int argc,char* argv[])
{
int socfd,nsfd,portno;
socklen_t size;
socfd=socket(AF_INET,SOCK_STREAM,0);
if(socfd==-1)
{printf("error opeing socket\n");exit(0);}
if(argc<2)
{
    printf("argument error");exit(0);
}
struct sockaddr_in cliaddr,seraddr;
char buf[100];
portno=atoi(argv[1]);
bzero((char*)&seraddr,sizeof(seraddr));
seraddr.sin_family=AF_INET;
seraddr.sin_addr.s_addr = htonl(INADDR_ANY);
seraddr.sin_port = htons(portno);
if (bind(socfd, (struct sockaddr *) &seraddr,sizeof(seraddr)) < 0)
             { printf("ERROR on binding\n");exit(0);}
     listen(socfd,5);

     while(1)
     {
size=sizeof(cliaddr);
nsfd=accept(socfd,(struct sockaddr *) &cliaddr,&size);
int c=fork();//creating child process   parent will accept client and each child will chat with each client 
if(c==0)
{
    close(socfd);
while(1)
{
printf("server is waiting\n");



memset(buf,0,100);
recv(nsfd,buf,100,0);
printf("client said\t %s\n",buf);
memset(buf,0,100);
printf("to client\t");
gets(buf);
send(nsfd,buf,100,0);



}}
else


{

close(nsfd);


}}

return 0;
}

Client Program
Input : Ip of Server And Port Number

#include<stdio.h>
#include<unistd.h>
#include<sys/socket.h>
#include<sys/types.h>
#include<netinet/in.h>
#include<stdlib.h>
#include<netdb.h>
#include<string.h>
#include<stdlib.h>
int main(int argc,char*argv[])
{int sockfd, portno, n;
    struct sockaddr_in serv_addr;
    struct hostent *server;

    char buffer[256];
    if (argc < 3) {
      printf("argument error");
       exit(0);
    }
    portno = atoi(argv[2]);
    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd < 0)
        {printf("error in socket");exit(0);}//creating socket
    server = gethostbyname(argv[1]);
    if (server == NULL) {
       printf("wrong hostname");
        exit(0);
    }
    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)
        {printf("connect error");exit(0);}//connecting to server

while(1)
{
    printf("Please enter the message: ");
    bzero(buffer,100);
    fgets(buffer,100,stdin);
send(sockfd,buffer,strlen(buffer),0);
bzero(buffer,100);
recv(sockfd,buffer,100,0);
printf("server said\t%s\n",buffer);

}

close(sockfd);
return 0;
}