UTF8 转GB 中文字符

std::string UTF8ToGB(const char* str)
{
	std::string result;
	WCHAR *strSrc;
	LPSTR szRes;

	//获得临时变量的大小
	int i = MultiByteToWideChar(CP_UTF8, 0, str, -1, NULL, 0);
	strSrc = new WCHAR[i + 1];
	MultiByteToWideChar(CP_UTF8, 0, str, -1, strSrc, i);

	//获得临时变量的大小
	i = WideCharToMultiByte(CP_ACP, 0, strSrc, -1, NULL, 0, NULL, NULL);
	szRes = new CHAR[i + 1];
	WideCharToMultiByte(CP_ACP, 0, strSrc, -1, szRes, i, NULL, NULL);

	result = szRes;
	delete[]strSrc;
	delete[]szRes;

	return result;
}