TCP socket programming instance 1-Client

/*
* Tcpclient. c
*/
# Include <sys/types. h>
# Include <sys/socket. h>
# Include <stdio. h>
# Include <stdlib. h>
# Include <errno. h>
# Include <string. h>
# Include <unistd. h>
# Include <netinet/in. h>
# Include <netdb. h>
# Define servport 1888
# Define maxdatasize 30
 
Int main (INT argc, char * argv [])
{
Int sockfd, sendbytes;
Char Buf [maxdatasize];
Struct hostent * Host;
Struct sockaddr_in serv_addr;
If (argc <2 ){
Fprintf (stderr, "Please enter the server's hostname! \ N ");
Exit (1 );
}
/* Get host */
If (host = gethostbyname (argv [1]) = NULL ){
Perror ("gethostbyname ");
Exit (1 );
}
/* Create socket */
If (sockfd = socket (af_inet, sock_stream, 0) =-1 ){
Perror ("socket ");
Exit (1 );
}
 
/* Set sockaddr_in parameters */
Serv_addr.sin_family = af_inet; // address cluster
Serv_addr.sin_port = htons (servport); // port number
Serv_addr.sin_addr = * (struct in_addr *) Host-> h_addr); // sever IP Address
Bzero (& (serv_addr.sin_zero), 8); // fill in 0 to keep the same size as struct sockaddr
 
/* Connect to sever */
If (connect (sockfd, (struct sockaddr *) & serv_addr, sizeof (struct sockaddr) =-1 ){
Perror ("Connect ");
Exit (1 );
}
 
/* Send MSG to server */
If (sendbytes = Send (sockfd, "hello", 5, 0) =-1 ){
Perror ("send ");
Exit (1 );
}
Close (sockfd );
}