#include <netinet/in.h>#include <arpa/inet.h>#include <unistd.h>#include <netdb.h>#include <stdio.h>int main(int argc, char *argv[]){char *host, **names,**addrs;struct hostent *hostinfo;if (argc == 1){	char myname[256];	gethostname(myname,255);	host = myname;}else 	host =argv[1];hostinfo = gethostbyname(host);if(!hostinfo){	fprintf(stderr, "cannot get info for host:%s\n",host);	exit(1);}printf("results for host %s:\n",host);printf("Name: %s\n",hostinfo->h_name);printf("Aliases:");names = hostinfo->h_aliases;while(*names){	printf(" %s",*names);	names++;}printf("\n");if(hostinfo->h_addrtype != AF_INET){	fprintf(stderr, "not an IP host!\n");	exit(1);}addrs = hostinfo->h_addr_list;while(*addrs){	printf(" %s",inet_ntoa(*(struct in_addr *)*addrs));	addrs++;}printf("\n");exit(0);}