From:	kagel AT quasar DOT bloomberg DOT com
Date:	Mon, 3 Feb 1997 12:51:31 -0500
Message-Id:	<9702031751.AA22023@quasar.bloomberg.com >
To:	invid AT dmv DOT com
Cc:	djgpp AT delorie DOT com
In-Reply-To:	<32F56281.2014@dmv.com> (message from Pyro Technic on Sun, 02 Feb 1997 19:58:57 -0800)
Subject:	Re: SIGSEV hates me
Reply-To:	kagel AT dg1 DOT bloomberg DOT com

   Date: Sun, 02 Feb 1997 19:58:57 -0800
   From: Pyro Technic <invid AT dmv DOT com>

   My prog is a stupid little prog for a math problem. It's due in 14
   hours. I need help bad.The prog, B low, compiles w/ just 1 warning

   D:\PROGS>gxx -o TOG.exe TOG#2.cpp
   TOG#2.cpp: In function `int main(...)':
   TOG#2.cpp:30: warning: implicit declaration of function `int getch(...)'

Include <conio.h> to remove this warning.  But is is not your problem, see below:

   [SNIP]
	   This is the program.

   <here>
   // Test of geinus problem #2 for 9th grade math

   #include <iostream.h>

   void main()
	   {
	   char dummy;
	   int num2, temp, digit[3], j, i;
	   float num1;

	   for(i=1; i < 10000; ++i)
		   {
		   num1 = i;
		   num2 = i * 4;
		   for(j=3; j>=0; ++j)

Here's your problem.  C array indices range from 0->(N-1) where N is the size
of the array.  The array digit is declared length 3, therefore, digit[j] where
j=3 is out of bounds; also your loop increments j to 4, 5, 6, etc instead of
decrementing without end (this is an infinite loop which eventually goes past
the end of allocated virtual memory pages and gets the SEGV)!  This should be:
EITHER

                   for(j=2; j>=0; j--)
OR
                   for(j=0; j<3; j++)
			   {
			   temp = (int)num1 % 10;
			   digit[j]=temp;
			   num1 /= 10;
			   num1 -= (temp/10); 
			   }
		   num1 = 0;
		   num1 = digit[0];
		   num1 += digit[1] * 10;
		   num1 += digit[2] * 100;
		   num1 += digit[3] * 1000;
		   if(num1==num2)
			   {
			   cout << '\n' << num1 << " * 4 = " << num2 << "\nPush a key to
   continue" << flush; 
			   dummy = getch();
			   }
		   else
			   cout << ".";
		   }	
	   }
   <to here>

   please answer, I'm a desperate newbie. Thanks in advance.

	   Pyro

-- 
Art S. Kagel, kagel AT quasar DOT bloomberg DOT com

A proverb is no proverb to you 'till life has illustrated it.  -- John Keats

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