Re: Beginner question

[Phil Marcelino <telcoman74@yahoo.com>]

Speed is a major advantage to pointers, but if you're
passing structures to a function (at least in C) they
get passed by value.  

This means that a copy of the original structure is
sent to the function, so whatever you do in within the
function to the structure has no effect on the main
structure itself.  In order to change a value in the
original structure you'll need to pass the pointer. 
(The only exception to this rule are arrays.)

This is my understanding of how it works in C.

I hope this helps.

Phil
--- wegifford <wegifford@GRUMPY.FORTLEWIS.EDU> wrote:
> Hey there,
>    I am a beginner and I am covering pointers and
> have a few questions.  The 
> book I am using is not giving me the best
> explanation.  The code makes tons of 
> sense but I want to know a little more about what a
> pointer is.
>    As I understand it a pointer variable is pointing
> to a variable location in 
> memory.  So when passed in a function it is not
> exactly being passed but where 
> the variable is located is being pass. What is a
> pointer exactly used for?  Is 
> the previous explantion the answer.  If so when is
> the best time to declare 
> and use pointers? What is a benefit of a pointer? Is
> it just speed?  Any help 
> you all could give would shed light on this concept.
> 
>                                                     
>    William
> 
> 
>
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