//------------------------------------------------------------
// Example program to demonstrate stacks with dynamic
//      array creation
//
// L.Aamodt
// 5/06/14
//------------------------------------------------------------

#include <iostream>
#include <cstdlib>

using namespace std;

const int DEFAULT_STACK_SIZE = 10;

class mystack                           // Class definition
{
    public:
        mystack();                      // Default constructor
        mystack(int size);
        bool Empty();
        void push(int value);
        int top();
        void pop();
        void display();

    private:                            // Data
        int stkTop, stkSize;
        //int stkArray[DEFAULT_STACK_SIZE];
        int *stkArray;
};

mystack::mystack()                      // Default constructor
{   stkTop = -1;
    stkArray = new int [DEFAULT_STACK_SIZE];   // array size hard coded
    stkSize = DEFAULT_STACK_SIZE;
}
mystack::mystack(int size)              // Constructor with size parameter
{   stkTop = -1;
    stkArray = new int [size];          // array size is a parameter
    stkSize = size;
}
void mystack::push(int value)           // Place another item on stack
{
 if (stkTop > stkSize - 2)
  {
      cerr << "stack overflow";
      exit(1);
  }
 else
 {
    stkTop = stkTop + 1;
    stkArray[stkTop]=value;
 }
    return;
}


void mystack::pop()                     // Remove top item from stack
{
if (stkTop == -1)
    {
    cerr << "stack is empty.  nothing to pop";
    exit(2);
    }
else
{
    stkTop = stkTop -1;
}
return;
}

int mystack::top()                      // Get a copy of the top item on stack
{
    int value;
    if (stkTop <= -1)
    {
        cerr << "stack empty" << endl;
        return 0;
        exit(3);
    }
    else
    {
        value = stkArray[stkTop];
        return value;
    }
}


void mystack::display()                   // Print stack contents
{
    if (stkTop == -1)
        cout << "Stack is Empty" << endl;
    else
    {
        cout << "Stack values are:" << endl;
        for (int i=0; i<=stkTop; i++ )
        {
            cout << stkArray[i] << endl;
        }
    }
    return;
}

int main()                                 // Test the stack functions
{
    mystack stack1;
    int i;

    for (i=0; i<10; i++)
    {
        stack1.push(i*10);
    }

    stack1.display();

    return 0;
}