daytime_client.c

#include <sys/socket.h>
#include <sys/types.h>
#include <netdb.h>
#include <netinet/in.h>
#include <unistd.h>
#include <arpa/inet.h>

int main(void){
    struct hostent *hostinfo = gethostbyname("time-a.nist.gov");
    if(!hostinfo) herror("gethostbyname");
    struct in_addr binIP = *((struct in_addr*) hostinfo->h_addr);
    printf("IP adresa: %s\n", inet_ntoa(binIP));

    int sok = socket(PF_INET, SOCK_STREAM, 0);
    if(sok == -1){perror("socket"); return 2;}

    struct sockaddr_in server;
    server.sin_family = AF_INET;
    server.sin_port = htons(13);
    server.sin_addr = binIP;
    memset(server.sin_zero, 0, 8);

    if(connect(sok, (struct sockaddr*)&server, sizeof(server)) == -1){
        perror("connect");
        return 1;
    }

    char buffer[200];
    int primljeno = 0;
    while(1){
        int novoprimljeno = recv(sok, buffer + primljeno,
                                 sizeof(buffer) - primljeno - 1, 0);
        if(novoprimljeno == 0) break;
        else if(novoprimljeno == -1) perror("recv");
        else primljeno += novoprimljeno;
    }
    buffer[primljeno] = 0;

    printf("%s\n", buffer);
    return 0;
}