Date: Wed, 27 Aug 1997 18:02:55 -0500 (CDT)
From: Andrew Deren <aderen AT eecs DOT uic DOT edu>
To: Paul Derbyshire <ao950 AT FreeNet DOT Carleton DOT CA>
cc: djgpp AT delorie DOT com
Subject: Re: Boy do I feel STUPID!! ....Files question...
In-Reply-To: <5tos0p$pdf@freenet-news.carleton.ca>
Message-ID: <Pine.SUN.3.95.970827180028.18092B-100000@bert.eecs.uic.edu>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Precedence: bulk

On 24 Aug 1997, Paul Derbyshire wrote:

> 
> "Locke" (lockeg AT usa DOT net) writes:
> > Hey everyone,
> > 
> > i am feeling really stupid, but i need help.  I have been working on this
> > game and it's going verrry well, but i've hit a wall.  I can't believe
> > this, but i can't remember how to write an array of structures to a file!
> > 
> > for instance... say i have a structure called S_MAP it goes as follows:
> > 
> > typedef struct
> > {
> >    char *name;
> >    int tiles[MAX_Y][MAX_X];
> > } S_MAP;
> > 
> > S_MAP Maps[MAX_MAPS];
> > 
> > 
> > That's a very watered down version of the structure, but it gets the idea
> > across...
> > Anyway, i want to write the variable Maps to a file and then later read it
> > back in.  I can't believe that I can write low level graphics routines, a
> > keyboard handler and all this really complicated stuff, but can't remember
> > how to write to a file.  Well, any help would be greatly appreceated...
> 
> fwrite(Maps,sizeof(S_MAP),MAX_MAPS,my_file_pointer_returned_by_fopen);
But you won't save char *name part of the structure. You only will save a
pointer to that name. I would consider changing declarations in S_MAP to
char name[15]; or whatever is the maximum number of chars in name.
You have to be careful about saving structs to disk. You have to watch out
for pointers inside the struct.


> 
> Two remarks: one: this is documented in the info files, info libc a
> fwrite. Two, this is a general C question, and might be better placed in
> comp.lang.c.
> --
>     .*.  Where feelings are concerned, answers are rarely simple [GeneDeWeese]
>  -()  <  When I go to the theater, I always go straight to the "bag and mix"
>     `*'  bulk candy section...because variety is the spice of life... [me]
> Paul Derbyshire ao950 AT freenet DOT carleton DOT ca, http://chat.carleton.ca/~pderbysh
> 


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