zby makes some good points , however has confused me one one issue

you even can write graphical applications in Perl if only you use a good library for the low level data munging.

Actually I suggest that perl is the perfect place to do your low level data munging, then begin plugging that data (I suggest you investigate the tutorials , pay particular note to using hashes and hash references) into you selected graphical library. If all you need is an image then probably GD is a good choice, if you're aiming for extra credit - do something funky with GTK or TK (make the rectangles move into place - whatever), my first suggestion would be to investigate Tk::Canvas , CPAN has been mis-behaving lately though so if search.cpan.org is unavailable - go googling.

Not having ever coded much in C or C++ (in fact I have only ever really hacked at existing code) , I suggest that perl can be very forgiving when you have a job that needs results NOW! , c/c++ can be rewarding when your program must produce the results FAST (no matter how long it takes to write).