Date: Mar 14, 2006 8:53 AM
Author: matt271829-news@yahoo.co.uk
Subject: Re: Reason for operator precedence

Dik T. Winter wrote:

> In article <1142342196.542632.294210@i39g2000cwa.googlegroups.com> matt271829-news@yahoo.co.uk writes:

> > Tony wrote:

> ...

> > > I was wondering what the reason is for having multiple levels of operator

> > > precedence?

> ...

> > 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

>

> That is not the reason. You could just as well have left to right

> operation when you use sufficiently many parenthesis in the euqations.

> E.g. 3*(4 + 6) = (3*4) + (3*6).

Well, obviously any precedence can be enforced with parentheses. I

meant make it work *without* the need for parentheses, just as in your

example below.

>

> But try to write the polynomial x^7 + 2x^6 - 3x^5 + 2x^4 +7x^3 - 3x^2 - 5x + 8

> without assuming precedence. It is to avoid large numbers of parenthesis.