C++ GET UTF-8网页编码转换

string UTF8ToGBK(const std::string& strUTF8)                                //GBKתUTF-8
{
int len = MultiByteToWideChar(CP_UTF8, 0, strUTF8.c_str(), -1, NULL, 0);
unsigned short * wszGBK = new unsigned short[len + 1];
memset(wszGBK, 0, len * 2 + 2);
MultiByteToWideChar(CP_UTF8, 0, (LPCTSTR)strUTF8.c_str(), -1, (LPWSTR)wszGBK, len);

len = WideCharToMultiByte(CP_ACP, 0, (LPWSTR)wszGBK, -1, NULL, 0, NULL, NULL);
char *szGBK = new char[len + 1];
memset(szGBK, 0, len + 1);
WideCharToMultiByte(CP_ACP,0, (LPWSTR)wszGBK, -1, szGBK, len, NULL, NULL);
//strUTF8 = szGBK;
std::string strTemp(szGBK);
delete[]szGBK;
delete[]wszGBK;
return strTemp;
}