Asked my professor today and he seemed to say that Global variables in general are bad.

I already kinda knew this was the case, but he didn't really say much about static global variables.

My question: Can you make a static global variable, if so, does it have the same pitfalls as a regular global variable?

ie: one that only works for the said file?

My example:

Working on a project that sorts latin words in a tree alphabetically. If the same occurrence of a word happens, instead of the add() function just returning and doing nothing, we need to add +1 to some integer counter.

I wanted to add a line of code in my add() function, so that in the case of return, it would be like



I wanted to do something like that. But he told me it would just be best to pass by reference. I already knew this was the way to go, but I am wondering if a static global

1) exists
2) serves any purpose without huge pitfalls.

This post was edited by Eep on Oct 24 2012 03:44pm

defining a variable as static just means that variable will retain its memory address no matter what. its generally used for passing arrays back to the function which called the funciton.

ex:



will create a static memory address that will not be demolished when the function returns meaning the user can use that address as they pleased where as




will return the address but your compiler will yell at you until you cry and there is no way to know if that memory address will indeed still be pointing to that string when the function returns. (most of the time it will not and you will either be pointed to garbage or get a segfult.)

This post was edited by AbDuCt on Oct 24 2012 03:46pm

so for my example I am better off just passing by ref then I suppose

in general you don't want to have any kind of mutable state in a global, because you have no control over who can update it and when... which means that any part of your program that depends on said global/state has unpredictable behavior at any given point in time.

generally when designing programs (or pieces of programs), your program's behavior should depend only on its inputs on and its internal state.

This post was edited by irimi on Oct 24 2012 05:34pm

+1 Thumbs up

why are you just necroing random threads for +1's.