datastructurelaboratory/Stacklinkedlist.java at main · SRINIVASAN2001/datastructurelaboratory · GitHub

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import static java.lang.System.exit;

class StackUsingLinkedlist {

    private class Node {

        int data;

        Node link;

    }

    Node top;

    StackUsingLinkedlist()

    {

        this.top = null;

    }

    public void push(int x)

    {

        Node temp = new Node();

        if (temp == null) {

            System.out.print("\nHeap Overflow");

            return;

        }

        temp.data = x;


        temp.link = top;


        top = temp;

    }


    public boolean isEmpty()

    {

        return top == null;

    }


    public int peek()

    {

        if (!isEmpty()) {

            return top.data;

        }

        else {

            System.out.println("Stack is empty");

            return -1;

        }

    }


    public void pop()

    {

        if (top == null) {

            System.out.print("\nStack Underflow");

            return;

        }

        top = (top).link;

    }


    public void display()

    {

        if (top == null) {

            System.out.printf("\nStack Underflow");

            exit(1);

        }

        else {

            Node temp = top;

            while (temp != null) {

                System.out.printf("%d->", temp.data);

                temp = temp.link;

            }

        }

    }

}

public class GFG {

    public static void main(String[] args)

    {

        StackUsingLinkedlist obj = new StackUsingLinkedlist();

        obj.push(11);

        obj.push(22);

        obj.push(33);

        obj.push(44);


        obj.display();


        System.out.printf("\nTop element is %d\n", obj.peek());


        obj.pop();

        obj.pop();

        obj.display();


        System.out.printf("\nTop element is %d\n", obj.peek());

    }

}