POV-Ray : Newsgroups : povray.off-topic : C++ classes and file i/o : Re: C++ classes and file i/o Server Time
5 Sep 2024 23:17:00 EDT (-0400)
  Re: C++ classes and file i/o  
From: stbenge
Date: 13 Apr 2009 21:02:38
Message: <49e3e0ae@news.povray.org>
Darren New wrote:
> stbenge wrote:
>> will work just fine elsewhere. Any help would be appreciated. I'm 
>> really stumped :(
> 
> Step one of being un-stumped is to figure out which of your assumptions 
> in the code is not holding true.
> 
> Print out fieldFileName.
> Print out fieldFile.
> Print out tempFx, tempFy, and val each time through the loop.
> Print out the return values from fread.
> print out sizeof(val).
> 
> The question you seek to answer is whether val is being read 
> incorrectly, or whether it's the assignment that is failing.

Thanks! I made my project a console application and printed the values 
as you suggested. I found out that by not explicitly assigning "val" (or 
tempFx, tempFy) an initial value, it was picking up nonsense and 
carrying it through as it read through the stream. I do not know why it 
would act this way inside a class member but not in other scenarios, but 
I suspect it has to do with how C++ allocates memory.

> I also wonder why you read tempFx and tempFy and then don't use them for 
> anything. I'm assuming this is some header?

Yes. The first two values in the binary file(s) describe the width and 
height of a playing field for a game. I dumped the values into useless 
variables so I could step through them without actually needing them, 
and wind up at the correct point in the stream to start reading values 
into the array. I may need to use these values another time, so I left 
that functionality in the binary format.

> Showing the declaration of the rest of the class (including map) is 
> probably a good idea.

I'm not sure I need to, now :)

Sam


Post a reply to this message

Copyright 2003-2023 Persistence of Vision Raytracer Pty. Ltd.