获取外网IP最简单的方法

std::string getOutIpaddress()
{
 std::string strRet = "";
 HRESULT hr = URLDownloadToFile(NULL,"http://www.3322.org/dyndns/getip","ip2city.dat",0,NULL);
 if (hr != S_OK)
 {
  return strRet;
 }

 char szBuffer[1024] = {0};
 memset(szBuffer,0,1024);

 FILE* fp = fopen("ip2city.dat","r");
 if (fp == NULL)
 {
  DeleteFile("ip2city.dat");
  return strRet;
 }

 fscanf(fp,"%s",szBuffer);
 fclose(fp);

 DeleteFile("ip2city.dat");

 strRet = szBuffer;

 return strRet;
}