C++ 字符串UTF-8与GBK转化

//UTF8转化为GBK格式

void ConvertUtf8ToGBK(CString &strUtf8)
{
int len=MultiByteToWideChar(CP_UTF8, 0, (LPCTSTR)strUtf8, -1, NULL,0);
wchar_t * wszGBK = new wchar_t[len];
memset(wszGBK,0,len);
MultiByteToWideChar(CP_UTF8, 0, (LPCTSTR)strUtf8, -1, wszGBK, len);

len = WideCharToMultiByte(CP_ACP, 0, wszGBK, -1, NULL, 0, NULL, NULL);
char *szGBK=new char[len + 1];
memset(szGBK, 0, len + 1);
WideCharToMultiByte (CP_ACP, 0, wszGBK, -1, szGBK, len, NULL,NULL);

strUtf8 = szGBK;
delete[] szGBK;
delete[] wszGBK;
}

//GBK转化为UTF8格式

void ConvertGBKToUtf8(CString &strGBK)
{
int len=MultiByteToWideChar(CP_ACP, 0, (LPCTSTR)strGBK, -1, NULL,0);
wchar_t * wszUtf8 = new wchar_t [len];
memset(wszUtf8, 0, len);
MultiByteToWideChar(CP_ACP, 0, (LPCTSTR)strGBK, -1, wszUtf8, len);

len = WideCharToMultiByte(CP_UTF8, 0, wszUtf8, -1, NULL, 0, NULL, NULL);
char *szUtf8=new char[len + 1];
memset(szUtf8, 0, len + 1);
WideCharToMultiByte (CP_UTF8, 0, wszUtf8, -1, szUtf8, len, NULL,NULL);

strGBK = szUtf8;
delete[] szUtf8;
delete[] wszUtf8;
}