Socket vježba (primjer klijent koda)

client.c

/*
** client.c -- a stream socket client demo
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#define PORT 3490 // the port client will be connecting to
#define MAXDATASIZE 100 // max number of bytes we can get at once

int main(int argc, char *argv[]){
	int sockfd, numbytes;
	char buf[MAXDATASIZE];
	struct hostent *he;
	struct sockaddr_in their_addr; // connector's address information
	if (argc != 2) {
		fprintf(stderr,"usage: client hostname\n");
		exit(1);
	}
	if ((he=gethostbyname(argv[1])) == NULL) { // get the host info
		perror("gethostbyname");
		exit(1);
	}
	if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
		perror("socket");
		exit(1);
	}
	their_addr.sin_family = AF_INET; // host byte order
	their_addr.sin_port = htons(PORT); // short, network byte order
	their_addr.sin_addr = *((struct in_addr *)he->h_addr);
	memset(&(their_addr.sin_zero), '\0', 8); // zero the rest of the struct
	if (connect(sockfd, (struct sockaddr *)&their_addr,
		sizeof(struct sockaddr)) == -1) {
		perror("connect");
		exit(1);
	}
	if ((numbytes=recv(sockfd, buf, MAXDATASIZE-1, 0)) == -1) {
		perror("recv");
		exit(1);
	}
	buf[numbytes] = '\0';
	printf("Received: %s",buf);
	close(sockfd);
	return 0;
}