🚀 go-pugleaf

surgsw@mizzou1.missouri.edu (Joel Weinstein) wrote:

>I know it's a lot to ask but I would appreciate it if you guys would
>explain pointers and structs things to me.  

ftp a copy of Snippets from any Simtel mirror.  It has an excellent
pointer tutorial in it by Ted Jenson.  

What do you not understand about structs?  A struct is merely a
collection of variables that may be handled together in some ways or
addressed individually.  It is usually a "natural" way to group things
that have something in common.  For example:

struct _car {
	short year;
	char model[36];
	char make[36];
	long miles;
};

A struct may contain any valid type including pointers, other structs,
and user defined types.  You may also have arrays of structs.

struct _family_assets{
	double cash_on_hand;
	double savings;
	struct _car car;
};

struct _family_assets assets;

To address an element of a struct, use the . operator like this:
	assets.cash_on_hand = 10000;
To address a struct within a struct, follow the same logic:
	assets.car.year = 1995;

To pass a struct, pass a pointer to it like this:

	/* prototype */
void my_func( struct *_family_assets);
	/* call */
my_func( &assets );

In my_func, to assign values, you must use the -> operator.  Use it
anytime you are using a struct pointer.

/* in my_func */
assets->savings = 25000;

What else do you need to know?

Bruce


	
Bruce D. Wedding                        Have Compiler, Will Travel!
Software Demi God                       
Katy, TX, USA #1

In article <48uf2k$nab@gryphon.phoenix.net>,
Bruce Wedding <brucew@phoenixnet> wrote:
>struct _car {

The problem here is that "_car" is in the implementation's namespace.

>To pass a struct, pass a pointer to it like this:

This is not necessary; ANSI mandates the passing of structs as normal
parameters, as well.

>What else do you need to know?

Worth mentioning:
foo->bar
is the same as
(*foo).bar

-s
p.s.: You should almost always pass pointer-to-struct; it is likely more
efficient.
-- 
Peter Seebach - seebs@solon.com - Copyright 1995 Peter Seebach.
C/Unix proto-wizard -- C/Unix questions? Send mail for help.  No, really!
Fund my computing hobby - send money! -- seebs@intran.xerox.com
The *other* C FAQ - ftp taniemarie.solon.com /pub/c/afq