Data Structures : Stack Implementation

Stack

#include <iostream>

using namespace std;

class Stack
{
private:
	int *node;
	int top, length;

public:
	Stack(int = 0);
	~Stack();

	void push(int);
	int pop();
	void display();
};

Stack::Stack(int size)
{
	top = -1;
	length = size;
	if (size == 0)
		node = 0;
	else
		node = new int[length];
}

Stack::~Stack()
{
	if (node != 0)
		delete[] node;
}

void Stack::push(int elem)
{
	if (node == 0)                //If the stack size is zero, allow user to mention it at runtime
	{
		cout << "Stack of zero size" << endl;
		cout << "Enter a size for stack : ";
		cin >> length;
		node = new int[length];
	}
	if (top == (length - 1))     //If the top reaches to the maximum stack size
	{
		cout << "\nCannot push " << elem << ", Stack full" << endl;
		return;
	}
	else
	{
		top++;
		node[top] = elem;
	}
}
int Stack::pop()
{
	if (node == 0 || top == -1)
	{
		cout << "Stack empty!";
		return -1;
	}
	int ret = node[top];
	top--;
	return ret;
}

void Stack::display()
{
	for (int i = 0; i <= top; i++)
		cout << node[i] << " ";
	cout << endl;
}

int main()
{
	Stack stack;


	for (size_t i = 0; i < 30; i++)
	{
		stack.push(i);
	}

	for (size_t i = 0; i < 20; i++)
	{
		stack.display();
	}

	cout << endl;

	for (size_t i = 0; i < 20; i++)
	{
		stack.pop();
		stack.display();
	}


	cin.get();
	cin.get();
}