Memory Fault- Core Dumped

[mlholder]

Hi all,

I am starting to learn about how to use stacks. However I am having a problem with popping off the stack. I was wondering if anyone could explain to me why my code will push onto the stack just fine, but I can't output when I pop. The error I get is memory fault (core dumped). It seems like if I push one piece of data onto the stack, then obviously the stack should not be empty. So I guess my question is why can I not pop the item off directly after pushing it on? I am using Unix through a Putty console if it makes any difference. This is an assignment for a data structures class and the instructor has provided the code for the implementation of the stack so I know that they are correct. Any ideas would be greatly appreciated.

#include <iostream>
#include <string>
#include <cstring>
#include "ansi.h"
#include "stack.h"

using namespace std;

int main()
{
   Stack<char> operands;
   Stack<char> numbers;
   char ans, inputArray[1024];
   int option;
   string input;

   do
   {
      cout << clearScreen << cursorPosition(1,1)
           << "Which type of expression do you wish to enter?" << endl << endl
           << "1. Infix Notation" << endl
           << "2. Reverse Polish Notation" << endl << endl
           << "Option: ";
      cin >> option;

      if(option == 1)
      {
         int left = 0, right = 0;
         cout << endl << "Expression: ";
         cin >> inputArray;

         //Check for matching parentheses
         for(int i = 0; inputArray[i] != '\0'; i++)
         {
            if(inputArray[i] == '(' )
               left++;
            else if(inputArray[i] == ')' )
               right++;
         }
         if(left != right)
         {
            cout << "Syntax Error" << endl;
            cout << "Try again (Y/N): ";
            cin >> ans;
         }


         cout << inputArray[0] << endl;
         //operands.push(inputArray[0]);

         //this is the line that causes the memory fault (core dumped) error
         //cout << operands.pop() << endl;
      }
      else
      {

      }

   }while(ans == 'Y' || ans == 'y');

   return 0;
}

[Peter87]

Is Stack your own class? Maybe one of the push and pop functions has a bug.

[mlholder]

The stack class was written by the instructor. There was also a file to test the stack operations and it works for ints. I just thought maybe I'm not using the stack itself correctly with char? In the instructor's test file:

#include <iostream>
#include "stack.h"

using namespace std;

int main(void)
{
Stack<int> s;

s.push(1);
s.push(2);
s.push(3);

while(!s.isEmpty() )
cout << s.pop() << endl;


return 0;
}


Like I said, everything works great if I use integers but I need it for chars. I am lost as to why I am getting this error. Thank you for your help.

[TwilightSpectre]

Have you tried running through it with a debugger? That can help a lot, and allows you to see exactly what is going on with the memory and why your program is crashing.

[mlholder]

Is it the same debugger as the gdb debugger? I've never known there was a debugger on the unix/putty terminal until recently.