if ((s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) exit(1);
if (connect(s, "checkip.dyndns.com", 80) < 0) exit(2);
if (send(s, "GET / HTTP/1.0\r\n\r\n") == -1) exit(3);
if ((r = recv(s)) == NULL) exit(4);
printf("%s\n", r);
if (!strstr(r, "HTTP/1.1 200 OK")) {
   i = substr(r, strstr(r, "IP Address: ") + 12, strlen(r));
   printf("IP Address: %s\n", left(i, strstr(i, "</body>")));
}
close(s);
exit(0);