Linux vs Windows: What do programmers use.

I was woundering if it is a common theme for most "Pro" programmers to use linux. I mean a book called C;Programming I have was written on linux. So which OS is it that programmers or hackers, per say, use?

Stick to ISO Standard C and it won't matter what OS you're using or even if there is an OS. A Standard C program will run on everything whether it's a PIC microcontroller, a PDP-10, an AS/400, a Lisp machine, or a Cray. Remember, a byte has CHAR_BIT bits.