IP Networking

main()
{
   	int   sd;
	struct   sockaddr_in server;
	char buf[512];
	int rc,len;

	server.sin_family = AF_INET;
   	server.sin_addr.s_addr = htonl(INADDR_ANY);
   	server.sin_port = htons(1234);

   	sd = socket (AF_INET,SOCK_DGRAM,0);

  	if(bind ( sd, &server, sizeof(server))==-1)
		printf("error\n");
	else
		printf("ok\n");

 	len=sizeof(server);
	printf("check\n");
   
    	printf("check1\n");
      	rc = recvfrom (sd, &buf[0], 2, 0,&server, &len);
      	printf("check2\n");
      	buf[rc]= '\0';
      	printf("Received: %s\n", buf);
}

main()
{

        int	sd,a;
	struct	sockaddr_in server;

	sd = socket (AF_INET,SOCK_DGRAM,0);

	server.sin_family = AF_INET;
	server.sin_addr.s_addr=htonl("127.0.0.1");
	server.sin_port = htons(1234);

	a=sendto(sd, "HI",2, 0,&server, sizeof(server));
        printf("sent=%d\n",a);
        exit(0);

}

//server
main()
{
        int   sd;
        struct   sockaddr_in server,clients;
        char buf[512];
        int rc,len;

        server.sin_family = AF_INET;
        server.sin_addr.s_addr = INADDR_ANY;
        server.sin_port = htons(1234);

        sd = socket (AF_INET,SOCK_DGRAM,0);

        if(bind ( sd, (struct sockaddr*)&server, sizeof(server))==-1)
                printf("error\n");
        else
                printf("ok\n");

        len=sizeof(clients);
        printf("check\n");

        printf("check1\n");
        rc = recvfrom (sd, &buf, 2, 0,(struct sockaddr*)&clients, &len);
        printf("check2\n");
        buf[rc]= '\0';
        printf("Received: %s\n", buf);
        return 0;
}


//client
main()
{

        int     sd,a;
        struct  sockaddr_in server;

        sd = socket (AF_INET,SOCK_DGRAM,0);

        server.sin_family = AF_INET;
        inet_aton("127.0.0.1",&(server.sin_addr));
        server.sin_port = htons(1234);

        a=sendto(sd, "HI",2, 0,(struct sockaddr*)&server, sizeof(server));
        printf("sent=%d\n",a);
        exit(0);

}