StackL.java

/*
Copyright (C) Deepali Srivastava - All Rights Reserved
This code is part of DSA course available on CourseGalaxy.com    
*/

package stackLinked;

import java.util.EmptyStackException;

public class StackL 
{
	private Node top;

    public StackL()
    {
      top=null;
    }
    
    public int size()
    {
    	int s=0;
    	Node p=top;
    	while(p!=null)
    	{
    		p=p.link;
    		s++;
    	}
    	return s;
    }

    public void push(int x)
    {
    	Node temp = new Node(x);
    	temp.link=top;
    	top=temp;
    }

    public int pop()
    {
       	int x;
    	if(isEmpty())
    	{
    		System.out.println("Stack Underflow\n");
    		throw new EmptyStackException();  
    	}
    	x=top.info;
    	top=top.link;
    	return x;
    }

    public int peek()
    {
    	if(isEmpty())
    	{
    		System.out.println("Stack Underflow\n");
    		throw new EmptyStackException();
    	}
    	return top.info;
    }

    public boolean isEmpty()
    {
    	return (top==null);
    }

    public void display()
    {       
    	Node p=top;
    	if(isEmpty())
    	{	
    		System.out.println("Stack is empty");
    		return;
    	}
    	
    	System.out.println("Stack is : ");
    	while(p!=null)
    	{
    		System.out.println(p.info + " ");
    		p=p.link;
    	}
    	System.out.println();
    }
}