Question

Assume you are working with a stack implementation of the linked list definition pasted below, write a member method “pop”.  The method should return a value (in the “popped” node).  Assume the existence of the node references called “TheStack” and “Top”. These references point to the start (or bottom) and top of the stack (or back of the list).

-------

Definition:

            class node {

          boolean data;

          node link;

}          

Answer 1

package stackLinkedList;

public class LinkedStack {

private int size;

private Node first;

/**

* Adds the item to this stack.

*/

public void push(Node node) {

node.link = first;

first = node;

size++;

}

/**

* Delete item from stack.

*/

public Node pop() {

if (isEmpty()) {

return null;

}

Node temp = first;

first = first.link;

size--;

return temp;

}

/**

* check stack is empty.

*/

public boolean isEmpty() {

return (first == null);

}

/**

* show all stack data

*/

public void displayStack() {

Node current = first;

while (current != null) {

current.displayNode();

current = current.link;

}

}

public static void main(String[] args) {

LinkedStack linkedStack = new LinkedStack();

linkedStack.push(new Node(true));

linkedStack.push(new Node(true));

linkedStack.push(new Node(false));

linkedStack.push(new Node(true));

linkedStack.push(new Node(true));

linkedStack.push(new Node(true));

linkedStack.displayStack();

System.out.println("Stack Size" + linkedStack.size);

Node popedNode=linkedStack.pop();

while (popedNode!=null) {

System.out.println("Stack Size" + linkedStack.size+"\t"+popedNode.data);

popedNode=linkedStack.pop();

}

}

}

//////////////////////Node class////////////////

package stackLinkedList;

public class Node {

public boolean data;

public Node link;

public Node(boolean data) {

this.data = data;

}

public void displayNode() {

System.out.println(data);

}

}

////////////////////////Output//////////////

true

true

true

false

true

true

Stack Size6

Stack Size5 true

Stack Size4 true

Stack Size3 true

Stack Size2 false

Stack Size1 true

Stack Size0 true