Using pop functions in Stacks - c++

Question

I am running through an example of a static stack implementation from a book, but was not able to obtain the correct value for the last integer popped of the stack. Particularly, the pop(int &) member function in the class IntStack is said to pop the last integer off the stack, and take as input the name of a reference to the integer value that was just "popped".
Upon compiling the code, I find that the input is assigned the value of the address rather than the integer value. I am unsure why this happens, and I am also unsure how the pop member function of the IntStack class assigns this input to the last value stored at index "top."
I've posted the class files for reference (copied from the book - note that these are 2 separate files, one header and one *.cpp). Any help understanding this is soooo greatly appreciated!!!!!
#include <stdio.h>
// Specification file for the IntStack class
#ifndef INTSTACK_H
#define INTSTACK_H
class IntStack
{
private:
int *stackArray; // Pointer to the stack array
int stackSize;
int top;
public:
// The stack size
// Indicates the top of the stack
// Constructor
IntStack(int);
// Copy constructor
IntStack(const IntStack &);
// Destructor
~IntStack();
// Stack operations
void push(int);
void pop(int &);
bool isFull() const;
bool isEmpty() const;
};
#endif
// Implementation file for the IntStack class
#include <iostream>
#include "IntStack.h"
using namespace std;
//************************************************
// Constructor *
// This constructor creates an empty stack. The *
// size parameter is the size of the stack. *
//************************************************
IntStack::IntStack(int size)
{
stackArray = new int[size];
stackSize = size;
top = -1;
}
//***********************************************
// Copy constructor *
//***********************************************
IntStack::IntStack(const IntStack &obj)
{
// Create the stack array.
if (obj.stackSize > 0)
stackArray = new int[obj.stackSize];
else
stackArray = nullptr;
// Copy the stackSize attribute.
stackSize = obj.stackSize;
// Copy the stack contents.
for (int count = 0; count < stackSize; count++)
stackArray[count] = obj.stackArray[count];
// Set the top of the stack.
top = obj.top;
}
//***********************************************
// Destructor *
//***********************************************
IntStack::~IntStack()
{
delete [] stackArray;
}
//*************************************************
// Member function push pushes the argument onto *
// the stack. *
//*************************************************
void IntStack::push(int num)
{
if (isFull())
{
cout << "The stack is full.\n";
}
else
{
top++;
stackArray[top] = num;
}
}
//*****************************************************
// Member function pop pops the value at the top *
// of the stack off, and copies it into the variable *
// passed as an argument. *
//*****************************************************
void IntStack::pop(int &num) {
if (isEmpty())
{
cout << "The stack is empty.\n";
}
else
{
top--;
}
}
//***************************************************
// Member function isFull returns true if the stack *
// is full, or false otherwise. *
//***************************************************
bool IntStack::isFull() const
{
bool status;
if (top == stackSize - 1)
status = true;
else
status = false;
return status;
}
//*****************************************************
// Member function isEmpty returns true if the stack *
// is empty, or false otherwise. *
//*****************************************************
bool IntStack::isEmpty() const
{
bool status;
if (top == -1)
status = true;
else
status = false;
return status;
}

Answer 1

pop method is missing num assignment
void IntStack::pop(int &num) {
if (isEmpty())
{
cout << "The stack is empty.\n";
}
else
{
num=stackArray[top];
top--;
}
}