AVR-Chat

Robert Adsett said:
> So in that case
>
>  for (int i = 0; i < x; i++) {
>        }
>  for( int j = 0; j < x; j++) {
>        }
>
>  would take no more room than
>
>  void func (void)
>  {
>  int i;
>
>  for ( i = 0; i < x; i++) {
>        }
>  for( i = 0; i < x; i++) {
>        }
>  }
>

I agree with what you're saying, but I think there's a condition you may
have omitted....


void func (void) {
{
    if (THIS_CONDITION_EVALUATES_TO_FALSE) {

        for (int i=0; i<x; i++) {
            for (int j=0; j<y; j++) {
            }
        }
    }
}

In the scenario described, you'd never push 'i' or 'j' onto the stack
unless the condition is true and the code executes.  I like to scope my
variables as close as possible to where they're needed, that way I won't
allocate memory that isn't going to be used.

And I definitely agree that a compiler should be smarter than me and it
should notice that I only use a variable as a loop index, and scope it
properly for me, but I don't know enough about compilers to say whether a
nice one like gcc does that or not.


Ethan
www.bufbotics.org