Program Stack_LIFO

Source Code Link Stack

/*
 * Linked List Berbasis Stack.
 *
 * @author  : Fauzan Azhmi Siregar
 * @id      : G1A011022
 * @class   : A
 */

class item
{
    public char data;
    public item next;
    public item prev;
    public item(char id)
    {
        data = id;
    }
    public void displayLink()
    {
        System.out.print("[" + data + "] ");
    }
}
class StackLink
{
    private item top;
    private item bottom;
    public StackLink()
    {
        top = bottom = null;
    }
    public boolean isEmpty()
    {
        return (top==null);
    }
    public void push(char id)
    {
        item newitem = new item(id);
        if (top == null)
        {
            top = bottom = newitem;
        }
        else
        {
            top.next = newitem;
            newitem.prev = top;
            top = newitem;
        }
    }
    public item pop()
    {
        item temp = null;
        if (top == null)
        System.out.print("Empty!");
        else if (top == bottom)
        {
            temp = top;
            top = bottom = null;
        }
        else
        {
            temp = top;
            top = top.prev;
            top.next = null;
        }
        return temp;
    }
    public void display()
    {
        item current = bottom;
        if (current == null)
            System.out.print("[ ]");
        else
            while(current != null)
            {
                current.displayLink();
                current = current.next;
            }
        System.out.print("");
    }
}

Source Code Stack

import java.util.*;
/*
 * Linked List Berbasis Stack.
 *
 * @author  : Fauzan Azhmi Siregar
 * @id      : G1A011022
 * @class   : A
 */

class Stack_LIFO
{
    public static void main(String[] args)
    {
        System.out.println("\t_Stack_Last_In_First_Out_\n");
        char p;
        Scanner in = new Scanner(System.in);
        StackLink theStack = new StackLink();
        do
        {           
            System.out.print("Input Data : ");
            char nilai = in.nextLine().charAt(0);
            theStack.push(nilai);
            System.out.print("Continue to Input Data (y/n) : ");
            p = in.nextLine().charAt(0);
        }
        while (p=='y' );
        System.out.print("\nData Stack : ");
        theStack.display();
        System.out.println("");
        System.out.println("\n\n\t_Stack Last In First Out (LIFO)_\n");
        System.out.print("Data In\t: ");
        theStack.display();
        System.out.print("  ==>  ");
        while( !theStack.isEmpty() )
        {
            item aLink = theStack.pop();
            aLink.displayLink();
            System.out.println("Out.\n");
            System.out.print("Last Data\t: ");
            theStack.display();
            System.out.print("  ==>  ");
        }
        System.out.println(" Empty! ");
    }
}