CS计算机代考程序代写 /* timeclnt.c – a client for timeserv.c

/* timeclnt.c – a client for timeserv.c
* usage: timeclnt hostname portnumber
*/
#include
#include
#include
#include
#include
#include
#include
#include

#define oops(msg) { perror(msg); exit(1); }

int 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 );
}