in reply to Perl & C/C++
You don't need to write code using a full blown GUI toolkit for a bar graph..there are graph modules for perl which make it very easy to construct a bar graph etc. GD::Graph, Chart::Graph to mention two such modules. These modules do use the GUI toolkits underneath, but you don't need to worry about the details too much.
You could of course choose C/C++, but why re-invent the wheel.
Chris