You could use sprintf or StringCchPrintf(). Here is an example from MSDN:
Code:
BOOL GetLastWriteTime(HANDLE hFile, LPTSTR lpszString, DWORD dwSize)
{
FILETIME ftCreate, ftAccess, ftWrite;
SYSTEMTIME stUTC, stLocal;
DWORD dwRet;
// Retrieve the file times for the file.
if (!GetFileTime(hFile, &ftCreate, &ftAccess, &ftWrite))
return FALSE;
// Convert the last-write time to local time.
FileTimeToSystemTime(&ftWrite, &stUTC);
SystemTimeToTzSpecificLocalTime(NULL, &stUTC, &stLocal);
// Build a string showing the date and time.
dwRet = StringCchPrintf(lpszString, dwSize,
TEXT("%02d/%02d/%d %02d:%02d"),
stLocal.wMonth, stLocal.wDay, stLocal.wYear,
stLocal.wHour, stLocal.wMinute);
if( S_OK == dwRet )
return TRUE;
else return FALSE;
}