How to get domain ip address using domain name in C++? - c++

Question

i am using visual c++,
I want to get a domain ip address from domain name..
how do i get it..
i already tried gethostbyname function...
here my code...
HOSTENT* remoteHost;
IN_ADDR addr;
hostName = "domainname.com";
printf("Calling gethostbyname with %s\n", hostName);
remoteHost =gethostbyname(hostName);
memcpy(&addr.S_un.S_addr, remoteHost->h_addr, remoteHost->h_length);
printf("The IP address is: %s\n", inet_ntoa(addr));
But i get a wrong ip address.

Answer 1

Here's complete source code to a little utility I find handy at times (I've named it "resolve"). All it does is resolve a domain name to a numeric IP (v4) address, and print it out. As-is, it's for Windows -- for Linux (or similar) you'd just need to get rid of the use_WSA class (and object thereof).
#include <windows.h>
#include <winsock.h>
#include <iostream>
#include <iterator>
#include <exception>
#include <algorithm>
#include <iomanip>
#include "infix_iterator.h"
class use_WSA {
WSADATA d;
WORD ver;
public:
use_WSA() : ver(MAKEWORD(1,1)) {
if ((WSAStartup(ver, &d)!=0) || (ver != d.wVersion))
throw(std::runtime_error("Error starting Winsock"));
}
~use_WSA() { WSACleanup(); }
};
int main(int argc, char **argv) {
if ( argc < 2 ) {
std::cerr << "Usage: resolve <host-name>";
return EXIT_FAILURE;
}
try {
use_WSA x;
hostent *h = gethostbyname(argv[1]);
unsigned char *addr = reinterpret_cast<unsigned char *>(h->h_addr_list[0]);
std::copy(addr, addr+4, infix_ostream_iterator<unsigned int>(std::cout, "."));
}
catch (std::exception const &exc) {
std::cerr << exc.what() << "\n";
return EXIT_FAILURE;
}
return 0;
}
This also uses the infix_ostream_iterator I've posted previously.