From:	"John M. Aldrich" <fighteer AT cs DOT com>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Program Crashes!!! Please help! Memory errors!!!
Date:	Tue, 23 Jun 1998 00:08:01 -0400
Organization:	Two pounds of chaos and a pinch of salt.
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Message-ID:	<358F2A21.525A5F2F@cs.com>
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To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Sal wrote:
> 
> OK....  I wrote this little program to sort a set of names and corresponding
> numbers.  It compiles fine... but when I run it it crashes.  It usually
> crashes in the middle of the data inpput part.  It tells me "Exiting due to
> signal SIGSEGV       General Protection Fault at eip=000058dc ........".
> Sometimes it gets past the data input part and gives me an "out of memory"
> error.  Sometimes it just prints out a bunch of garbage and hangs.  I'm new
> to C++ so excuse my ignorance of these things.  Whenever I used to program
> in Pascal I never had any type of memory problems...

That's because Pascal protects programmers against things like writing
past array boundaries.  Make the following change in main() and your
program should work:

>  string datast[num-1];
>  int data[num-1];

  string datast[num];
  int data[num];

Some other tips:

 - There should be no space after the # in a preprocessor directive.
 - In a for loop that goes from 0 to n-1, the clearest statement is
thus:

   for ( int i = 0; i < num; i++ )

   not

   for ( int i = 0; i <= num - 1; i++ )

 - void is an illegal return type for main().  See chapter 11 of the
comp.lang.c FAQ (http://www.eskimo.com/~scs/C-faq/top.html) for more
information.
 - Always compile programs with at least the flags '-Wall' and '-O'; the
compiler can catch lots of mistakes if you let it.

Hope this helps!

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