Stacks (thing)

Somewhat generic stack code. Data is an int for simplicity. It should work, but I make no guarantees!!

/*
     stack.h - header file for a stack data structure.
*/

#ifndef STACK_H
#define STACK_H

#include <stdlib.h>
#include <iostream.h>

class node;
class stack;

class node
{
    friend stack;
    private:
        int data;
        node *link;
};

class stack
{
    public:
        stack();
        ~stack();
        int peek();
        int pop();
        void push( int loc );
        bool isEmpty();
        int size();
    private:
        node * first;
        bool empty;
        int howBig;
};

#endif                          //STACK_H


/*
  stack.cpp
  source code for a stack data structure, implemented using a linked list
*/

#include "stack.h"

stack::stack()
{
    first = new node;
    first->link = 0;
    //empty = true;
    howBig = 0;
}

stack::~stack()
{
    node * next;

    while ( first != 0 ) {
        next = first->link;
        delete first;
        first = next;
    }
}

int stack::peek()
{
    return first->data;
}

int stack::pop()
{
    if ( ! isEmpty() ) {
        int x = first->data;
        node *temp = first;
        first = first->link;
        howBig--;
        delete temp;
        return x;
    } else {
        cerr << "Stack is empty.\n";
        exit( 1 );
        return 0;   //  MSVC insists that all control paths must 
                    //  return a value. Duhhh...
    }
}

bool stack::isEmpty()
{
    return ( first == 0 );
}

void stack::push( int loc )
{
    empty = false;
    node *temp = new node;
    temp->data = loc;
    temp->link = first;
    first = temp;
    howBig++;
    return;
}

int stack::size()
{
    return howBig;
}