/* timeclnt.c - a client for timeserv.c *              usage: timeclnt hostname portnumber */#include       <stdio.h>#include       <sys/types.h>#include       <sys/socket.h>#include       <netinet/in.h>#include       <netdb.h>#define        oops(msg)       { perror(msg); exit(1); }main(int ac, char *av[]){	struct sockaddr_in  servadd;        /* the number to call */	struct hostent      *hp;            /* used to get number */	int    sock_id, sock_fd;            /* the socket and fd  */	char   message[BUFSIZ];             /* to receive message */	int    messlen;                     /* for message length */     /*      * Step 1: Get a socket      */	sock_id = socket( AF_INET, SOCK_STREAM, 0 );    /* get a line   */	if ( sock_id == -1 ) 		oops( "socket" );          		/* or fail      */     /*      * Step 2: connect to server      *         need to build address (host,port) of server  first      */	bzero( &servadd, sizeof( servadd ) );   /* zero the address     */	hp = gethostbyname( av[1] );            /* lookup host's ip #   */	if (hp == NULL) 		oops(av[1]);            	/* or die               */	bcopy(hp->h_addr, (struct sockaddr *)&servadd.sin_addr, hp->h_length);	servadd.sin_port = htons(atoi(av[2]));  /* fill in port number  */	servadd.sin_family = AF_INET ;          /* fill in socket type  */						       /* now dial     */	if ( connect(sock_id,(struct sockaddr *)&servadd, sizeof(servadd)) !=0)	       oops( "connect" );     /*      * Step 3: transfer data from server, then hangup      */	messlen = read(sock_id, message, BUFSIZ);     /* read stuff   */	if ( messlen == - 1 )	       oops("read") ;	if ( write( 1, message, messlen ) != messlen )  /* and write to */	       oops( "write" );                        /* stdout       */	close( sock_id );    }