where is the line (to be processed) stored?

In my comment I assumed it's a line in a file and that the termination condition is eof, but you can generalize to any aggregate of items. I'm just combining the test with the increment step so we can use a simple while loop without having to peel the 'first increment' step out of the loop. If that makes any sense :)

Thanks.

I was trying to point out that the idiom becomes while(line=readline()) which I'd rather avoid since = and == often get confused in a conditional.

It would normally be silly to get into this level of detail but I use this so often.

Oh, good point. I am tolerant of globals :). Also of assignment instead of equality in conditionals (with an extra layer of parens to flag their unconventional nature). I've also used class methods where the implicit variable is in this.