Re: FOR loop limit

On 02/02/2009, at 11:41 PM, Vern Hamberg wrote:

I'm trying to figure this out, too. This is how a FOR loop is supposed
to operate - the test exceeds the limit.

That's correct.

The original question was why we start with 1

No, the original was a comment on observed behaviour i.e., that the index variable must be capable of holding a value at least 1 greater than the loop limit. That lead on to a pointless discussion of "Why is it so?" which in turn lead to unfounded supposition that the starting value may have some bearing on the terminal value.

- example given was a FOR
loop - but I suspect the question was really about array bases -
zero-based for C/C++, say.

No, more that loops are frequently used to iterate over arrays therefore the starting value must have some relationship to the index of an array element. Some languages let you choose the boundary range--negative array indices anyone? In non-C-derived languages arrays are generally 1-based, In C-derived languages arrays are generally 0-based. However, in all programming languages (at least that I can think of), on for-loop termination, the index of the loop is always 1 greater than the terminal value--regardless of the starting value.

I and others have offered some speculation on
that, and have moved tangentially into errors when the loop counter may
exceed the limits of the data type used for that variable. So I'm flatly
getting a little lost!! See my last post in response to this.

No, that's where we started so if we're back to range errors on the loop index then we've come full-circle. So what are we discussing again?


Regards,
Simon Coulter.
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