stack_Array.cpp

#include <iostream>
#include <cstdlib>
using namespace std;

// define default capacity of the stack
#define SIZE 10

// Class for stack
class stack
{
	int *arr;
	int top;
	int capacity;

public:
	stack(int size = SIZE); 	// constructor
	~stack();   				// destructor

	void push(int);
	int pop();
	int peek();

	int size();
	bool isEmpty();
	bool isFull();
};

// Constructor to initialize stack
stack::stack(int size)
{
	arr = new int[size];
	capacity = size;
	top = -1;
}

// Destructor to free memory allocated to the stack
stack::~stack()
{
	delete arr;
}

// Utility function to add an element x in the stack
void stack::push(int x)
{
	if (isFull())
	{
		cout << "OverFlow\nProgram Terminated\n";
		exit(EXIT_FAILURE);
	}

	cout << "Inserting " << x << endl;
	arr[++top] = x;
}

// Utility function to pop top element from the stack
int stack::pop()
{
	// check for stack underflow
	if (isEmpty())
	{
		cout << "UnderFlow\nProgram Terminated\n";
		exit(EXIT_FAILURE);
	}

	cout << "Removing " << peek() << endl;

	// decrease stack size by 1 and (optionally) return the popped element
	return arr[top--];
}

// Utility function to return top element in a stack
int stack::peek()
{
	if (!isEmpty())
		return arr[top];
	else
		exit(EXIT_FAILURE);
}

// Utility function to return the size of the stack
int stack::size()
{
	return top + 1;
}

// Utility function to check if the stack is empty or not
bool stack::isEmpty()
{
	return top == -1;	// or return size() == 0;
}

// Utility function to check if the stack is full or not
bool stack::isFull()
{
	return top == capacity - 1;	// or return size() == capacity;
}

// main function
int main()
{
	stack pt(3);

	pt.push(1);
	pt.push(2);

	pt.pop();
	pt.pop();

	pt.push(3);

	cout << "Top element is: " << pt.peek() << endl;
	cout << "Stack size is " << pt.size() << endl;

	pt.pop();

	if (pt.isEmpty())
		cout << "Stack Is Empty\n";
	else
		cout << "Stack Is Not Empty\n";

	return 0;
}