JAVA - LinkedList Stack

 

run:

Element at the top is :8

Element removed is : 8

The size of the stack is : 2

Element removed is : 3

Element at the top is : 9

Stack is empty :  false

BUILD SUCCESSFUL (total time: 0 seconds)

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https://www.scaler.com/topics/java/stack-and-queue-in-java/

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package linkliststack;

import java.util.*;

public class LinkListStack {

    private Node headNode; // the first node

    private int stackSize;

    // nest class to define linkedlist node

    private class Node {

        int value;

        Node next;

    }

    public LinkListStack() {

        headNode = null;

        stackSize = 0;

    }

    // Remove value from the beginning of the list to demonstrate behaviour of the stack

    public int pop() throws Exception {

        if (headNode == null) {

            throw new EmptyStackException();

        }

        int value = headNode.value;

        headNode = headNode.next;

        stackSize--;

        return value;

    }

    // Add value to the beginning of the list to demonstrate the behaviour of the stack

    public void push(int value) {

        Node oldHead = headNode;

        headNode = new Node();

        headNode.value = value;

        headNode.next = oldHead;

        stackSize++;

    }

    public int peek() throws Exception {

        if (headNode == null) throw new EmptyStackException();

        else return headNode.value;

    }

    public int size() {

        return stackSize;

    }

    public boolean empty() {

        return stackSize == 0;

    }

    public static void main(String args[]) throws Exception {

        LinkListStack mystack = new LinkListStack();

        mystack.push(9); //a

        mystack.push(3); //b    

        mystack.push(8); //c 

        System.out.println("Element at the top is :" + mystack.peek()); //d

        System.out.println("Element removed is : " + mystack.pop()); //e

        System.out.println("The size of the stack is : " + mystack.size()); //f

        System.out.println("Element removed is : " + mystack.pop()); //g

        System.out.println("Element at the top is : " + mystack.peek()); //h

        mystack.push(10);

        System.out.println("Stack is empty :  " + mystack.empty()); //i

    }

}