C++ boost::asio programming-detailed introduction to domain name resolution

#include "stdafx.h" 
#include "boost/asio.hpp" 
#include "boost/shared_ptr.hpp" 
#include "boost/thread.hpp" 
#include <boost/lexical_cast.hpp>//使用字符串转换功能 
   
using namespace std; 
using namespace boost::asio; 
   
#ifdef _MSC_VER 
#define _WIN32_WINNT  0X0501 //避免VC下编译警告 
#endif 
   
//域名解析为IP 
//入参：域名，端口 
//返回：ip地址 
vector<string> domain2ip(const char *domain,int port) 
{ 
  io_service ios; 
  //创建resolver对象 
  ip::tcp::resolver slv(ios); 
  //创建query对象 
  ip::tcp::resolver::query qry(domain,boost::lexical_cast<string>(port));//将int型端口转换为字符串 
  //使用resolve迭代端点 
  ip::tcp::resolver::iterator it=slv.resolve(qry); 
  ip::tcp::resolver::iterator end; 
  vector<string> ip; 
  for(;it!=end;it++) 
  { 
    ip.push_back((*it).endpoint().address().to_string()); 
  } 
  return ip; 
} 
   
int _tmain(int argc, _TCHAR* argv[]) 
{ 
  vector<string> ip=domain2ip("www.csdn.net",0); 
  for(int i=0;i<ip.size();i++) 
  { 
    cout<<ip[i]<<endl; 
  } 
  getchar(); 
  return 0; 
}