For loops

[tanffn]

[pascal]For I:= 0 to –1 do beep();[/pascal]
How many time beep() will be preformed?

[Paizo]

:lol:
what kind of test is that? :lol:

[FNX]

I really don't understand if this would be a trick or something... :? :lol:

[JSoftware]

In the former version of my script language the answer would have been 1

[Robert Kosek]

0. Because once you click compile, Delphi, and even Freepascal, would beat you over the head with a very large hammer.

[JernejL]

probably 0 times, unless the overflow checking is OFF, in that case it will go around and beep 4294967295 times.

[Nitrogen]

zero times, surely!?

I routinely use this sort of code:

For I := 0 to high(GameObjects) do something;

And if high(GameObjects) returns -1, as it does when the program is first run, it just skips the for loop.

[WILL]

Well technically if there is a thunderstorm outside and your computer is right beside the window and a bolt of lightning hits your computer case and zaps the guts of it right as you hit F9, it could possibly end up doing a single beep as it powers down it's newly fried circuits.

[tanffn]

The reason I asked this is because I had a similar code to that (only difference was that -1 was a var) that compiled and ran as 90% expected (if the var was –1 it didn’t enter the loop) using Delphi6.
Few weeks ago I needed to add a few features to that application and I decided to do it with Delphi2006. The new futures I added worked fine but accompanied with it was a strange new bug..

Long story short, after several hours of debugging I found the problem with the for loop. It wasthe exact same code that worked fine in Delphi6, but in Delphi2006 I had to add an If statement before the loop!

It’s the first time I encountered this kind of behavior with for loops.. but hey, I’ve seen worse :?

[WILL]

The most common case I've seen for needing an if statement before a for loop was when you are accessing object classes within that loop that may not have it's first element created so you'll get a memory error because the class was not pointing to memory that was allocated.

Other than that I don't see much reason to use an if statement as I've come to understand the language. Maybe avoid triggering an over anxious debugger?