Date: Mar 14, 2006 8:16 AM
Author: matt271829-news@yahoo.co.uk
Subject: Re: Reason for operator precedence


Tony wrote:
> Hi all.
>
> Hope this isn't a silly question.
>
> I was wondering what the reason is for having multiple levels of operator
> precedence?
>
> Phrased another way, why is it that we don't just evaluate everything from
> left to right?
>
> Having multiple levels of precedence obviously adds complexity, so I assume
> there must be some payback. However, I don't see what it is.
>


As far as addition/subtraction vs multiplication/division is concerned,
one reason is to ensure that the distributive property of
multiplication works sensibly. For example, we want 3*(4 + 6) = 3*4 +
3*6 = 3*(6 + 4) = 3*6 + 3*4.

And for exponentiation we want, for example, 3*3^2 = 3^3, not (3*3)^2