Creating Your Own Stack

This will teach you how to implement Interface and creating your own stack methods.

This is the stack interface

Using the LinkedList Java Collection Framework ( JCF ) to create the stack methods

/* This is thee LinkedList stack class */ import java.util.LinkedList; /** * * @author JJ */ public class LinkedListStack implements StackInterface { LinkedList start; //Create a new empty LinkedList LinkedListStack() { start = new LinkedList(); } //Look at the top element on the stack without removing it public Object peek() { if(start.isEmpty()) { System.out.println("Stack is empty"); } return start.getLast(); } //Removing the recent added element from the stack public Object pop() { if(start.isEmpty()) { System.out.println("Stack is empty"); } return start.removeLast(); } //Add elements into the list public void push(Object o) { start.add(o); } //Returns the size of the stack public int size() { return start.size(); } //Print the element in the stack public void display() { if(start.isEmpty()) { System.out.println("The stack is empty"); } else { for(int i = size(); i > 0; i--) { System.out.println(start.get(i-1)); } } } }

Now we will test the stack method by creating a driver

/* This is the LinkedList driver */ /** * * @author JJ */ import java.util.*; public class LinkedListDriver { public static void main(String[] args) { LinkedListStack stack = new LinkedListStack(); String getName; Scanner key = new Scanner(System.in); /* * Get inputs from the user */ for(int i =0; i<3; i++) { //Get the input from the user System.out.print("\nEnter name: "); getName = key.next(); //Add the user input into the stack stack.push(getName); //Output the elements in the stack System.out.println("The stack is\n" ); stack.display(); //Output the size of the stack System.out.print("\nThe size now is " + stack.size() + "\n"); //Look at the top element of the stack without removing it System.out.println("The last element added is " + stack.peek()); } //Remove the recent added element System.out.println("\nNow removing the recent added element " + stack.pop()); System.out.println("The new stack is\n"); //Prints out the elements in the stack stack.display(); //Prints out the new size of the stack System.out.println("The new size is " + stack.size()); /* * Get inputs from the user */ for(int i =0; i<3; i++) { //Get the input from the user System.out.print("\nEnter name: "); getName = key.next(); //Add the user input into the stack stack.push(getName); //Output the elements in the stack System.out.println("The stack is\n" ); stack.display(); //Output the size of the stack System.out.print("\nThe size now is " + stack.size() + "\n"); //Look at the top element of the stack without removing it System.out.println("The last element added is " + stack.peek()); } //Remove the recent added element System.out.println("\nNow removing the recent added element " + stack.pop()); System.out.println("The new stack is\n"); //Prints out the elements in the stack stack.display(); //Prints out the new size of the stack System.out.println("The new size is " + stack.size()); } }

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