Linux网络程序设计之使用gethostbyname和gethostbyaddr函数

在已知亚马逊主站域名（www.amazon.com）的前提下，通过调用gethostbyname( )函数，来获取IP地址；通过该IP地址调用gethostbyaddr( )来获取亚马逊主站的主机信息，并打印到控制台

#include<string.h>
#include<stdio.h>
#include<arpa/inet.h>
#include<sys/socket.h>

int main()
{
    char host[]="www.amazon.com";
    struct hostent *ht1=NULL,*ht2=NULL;
    char str[30];
    ht1=hethostbyname(host);
    if(ht1)
    {
        printf("ip:%s\n",inet_ntop(ht1->h_addrtype,ht1->h_addr_list[0],str,30));
        
    }
    else
    {
        printf("error!\n");
    }
    
    int type=ht1->h_addrtype;
    ht2=gethostbyaddr(str,30,type);
    if(ht2)
    {
        printf("name:%s\n",ht2->h_name);
        printf("length:%d\n",ht2->h_length);
        for(int i=0;;i++)
        {
            if(ht2->h_aliases[i]!=NULL){
                printf("alias %d:%s\n",i,ht2->h_aliases[i]);
                
            }
            else
            {
                break;
            }
        }
    }
    else
    {
        printf("error2!\n");
    }
    return 0;
 }