On Wed, 2009-10-07 at 13:24 -0700, Tommy Pham wrote:
>
>
> ________________________________
> From: tedd <tedd.sperling@xxxxxxxxx>
> To: php-general@xxxxxxxxxxxxx; ash@xxxxxxxxxxxxxxxxxxxx; Daevid Vincent <daevid@xxxxxxxxxx>
> Sent: Wed, October 7, 2009 12:42:41 PM
> Subject: RE: Whacky increment/assignment logic with $foo++ vs ++$foo
>
> At 1:59 PM +0100 10/7/09, Ashley Sheridan wrote:
> >>On Wed, 2009-10-07 at 08:54 -0400, tedd wrote:
> >>At 6:15 PM -0700 10/6/09, Daevid Vincent wrote:
> >>>Except that:
> >>>
> >>>$a = 123;
> >>>$b = $a++;
> >>>echo $b; //gives 123, not 124
> >>>
> >>>as you logically expect it to and common sense would dictate, regardless of
> >>>what K&R or anyone else says.
> >>
> >>That's not the way I look at it.
> >>
> >> $b = $a++;
> >>
> >>means to me "take the value of $a and assign to $b and then increment $a."
> >>
> >>Whereas:
> >>
> >> $b = ++$a;
> >>
> >>means to me "increment $a and take the value of $a and assign to $b."
> >>
> >>Cheers,
> >>
> >>tedd
> >>
> >>
> >
> >Which is exactly the reason for the two operators in C.
> >
> >Thanks,
> >Ash
>
> Ash:
>
> The reason was simply to provide a different way of doing something.
> For example, take the statements of:
>
> $a = 10;
> $b = a$++; // $b = 10 and $a = 11
>
> This post-increment operator was a way to assign 10 to $b and
> increment $a in one statement.
>
> Whereas:
>
> $a = 10;
> $b = ++a$; // $b = 11 and $a = 11
>
> This pre-increment operator was a way to increment $a and also assign
> that value to $b.
>
> Both are perfectly valid ways of using the operator. Also realize
> that the pre-decrement and post-decrement operators worked in similar
> fashion.
>
> Now why would someone want to do that? There could be many reasons,
> but that was left to the programmer to use as he/she needed.
>
> However, what I find wacky about all of this is:
>
> for($i=1; $i<=10; $i++)
> {
> echo($i);
> }
>
> and
>
> for($i=1; $i<=10; ++$i)
> {
> echo($i);
> }
>
>
> Do exactly the same thing. I would have expected the first to print
> 1-10, while the second to print 2-10, but they both print 1-10.
>
> Cheers,
>
> tedd
>
>
> Tommy>> Why would expect to print 2-10? The way I read the for loop is: start $i with 1, do loop body until $i <= 10, increment $i before next loop. So whether post/pre-increment doesn't matter logically. Moreover, your loop can also be written as:
>
> for ($i=1; $i <= 10;)
> {
> echo ($i++);
> }
>
> PS: I hate to send reply in 'rich text' but Yahoo's plain text screw up the quote... I think it's time to switch over to gmail...
>
>
> --
> -------
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>
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That what I thought I said when I said "Which is exactly the reason for
the two operators in C."
Thanks,
Ash
http://www.ashleysheridan.co.uk
