I read all over the web about how scripting programming languages (like ruby or python) are fast for writing programs quickly. so i would like you to consider a programming project that is :

1- the length of source code is in the magnitude of few hundreds to few thousands lines of code.
2- not a low level (driver / OS level) program.

question : since developing my program in ruby or python will be much faster(i assume) what are the reason(s) why i should consider using c++ over ruby /python for such project ?

sharing your practical experience will be greatly appreciated.

thank you