> i study software engineering and only for study purposes
> i want to study the code of your program,so if u can tell
> me what subjects or programming languages should i know
> to understand the code and how i can compile the 
win_source
> (how i can open the whole project with vc++ 6).

Err, to understand the code wil be a bit hard - you have to 
have good knlowledge of various Internet standards (RFC), 
good C skills (I mean good enough to understand the code 
which is often a bit obscure, that is, quite good 
actually), and good developing skills in general.. 
compiling the code is not so difficult for someone skilful 
(copy all src/* sources in C:\Dev and src_win/* ones in 
C:\Dev\Winhttrack ; and don't forget to install both 
service packs AND ipv6 support)