64-bit integer under VC6

see http://www.cnitblog.com/cockerel/archive/2006/08/16/15356.aspx

using __int64 and unsigned __int64

generally it works fine (as you're using ordinary int / unsigned int), and the only problem i encountered until now is that, you cannot use cout<< (cin) to output (input) them, which means that you need to handle them seperately...