package stackQueue;

/* Manually implement a Java Stack of integers */

public class StackInt extends StackQueueInt {

/* Constructor for the StackInt Class */

StackInt() {

/* Create the superClass */

super();

/* Initialize the head to be null */

head = null;

}

/* Push data onto the stack */

public void push (int newData) {

/* Create a new node to add to the stack */

Node newNode = new Node(newData);

/* Initialize the next pointer on the new node to point to the previous head */

newNode.next = head;

/* The new head is the new Node */

head = newNode;

}

/* Pop data off the stack */

public int pop () {

if (head == null) {

throw new IllegalStateException("Can't pop off of an empty list");

}

/* Save the value to return */

int returnValue = head.data;

/* Remove the node from the head of the Stack */

head = head.next;

/* Return the popped value */

return returnValue;

}

}