[C++] 16진수 문자열을 2진수 문자열로 변환

CString strhex = _T("8CEF");
_tprintf(_T("hex: %s \n"), (LPCTSTR)strhex);

unsigned long dec = _tcstoul(strhex, NULL, 16);
_tprintf(_T("dec: %d \n"), dec);

CString bin;
CString buf;
TCHAR mod[2];
do
{
    _ultot(dec % 2, mod, 2);
    buf = mod;
    buf += bin;
    bin = buf;
} while (dec = dec / 2);
_tprintf(_T("bin: %s \n"), (LPCTSTR)bin);

CString strhex = _T("8CEF");
_tprintf(_T("hex: %s \n"), (LPCTSTR)strhex);

unsigned long dec = _tcstoul(strhex, NULL, 16);
_tprintf(_T("dec: %d \n"), dec);

TCHAR bin[1024];
_ultot(dec, bin, 2);
_tprintf(_T("bin: %s \n"), bin);