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