/* $begin hostinfo */
#include "csapp.h"

int main(int argc, char **argv) 
{
    char **pp;
    struct in_addr addr;
    struct hostent *hostp;

    if (argc != 2) {
	fprintf(stderr, "usage: %s <domain name or dotted-decimal>\n", 
		argv[0]);
	exit(0);
    }

    if (inet_aton(argv[1], &addr) != 0) 
	hostp = Gethostbyaddr((const char *)&addr, sizeof(addr), AF_INET); 
    else                                
	hostp = Gethostbyname(argv[1]);

    printf("official hostname: %s\n", hostp->h_name);

    for (pp = hostp->h_aliases; *pp != NULL; pp++)
	printf("alias: %s\n", *pp);

    for (pp = hostp->h_addr_list; *pp != NULL; pp++) {
	addr.s_addr = ((struct in_addr *)*pp)->s_addr;
	printf("address: %s\n", inet_ntoa(addr));
    }
    exit(0);
}
/* $end hostinfo */