MyStack.java Implement a stack using linked lists data structure. Implement your

ID: 3748308 • Letter: M

Question

MyStack.java Implement a stack using linked lists data structure. Implement your own linked list. You cannot use Java's java.util.LinkedList. pop0: returns and removes the last value on the stack push(String item): Push a given value onto the stack .isEmpty0: returns true or false depending on if the stack is empty printStack0: prints the items on the stack to console . Handles errors for all possible edge cases (i.e. doesn't throw an unhandled exception to the user) ·MyStack(String[] list): constructor which creates the stack with the items in list on the stack. So if list had {"a", "b", "c"} the stack would look like: "c" on top of "b" on top of "a"

Explanation / Answer

SOlution:

StackImplementation.java#############

import java.util.*;

/* Class Node */
class Node
{
    protected String data;
    protected Node link;

    /* Constructor */
    public Node()
    {
        link = null;
        data = null;
    }
    /* Constructor */
    public Node(String d,Node n)
    {
        data = d;
        link = n;
    }
    /* Function to set link to next Node */
    public void setLink(Node n)
    {
        link = n;
    }
    /* Function to set data to current Node */
    public void setData(String d)
    {
        data = d;
    }
    /* Function to get link to next node */
    public Node getLink()
    {
        return link;
    }
    /* Function to get data from current Node */
    public String getData()
    {
        return data;
    }
}

/* Class linkedStack */
class MyStack
{
    protected Node top ;
    protected int size ;

    /* Parameterized Constructor */
    public MyStack(String[] list)
    {
        //Pushing list of the data into the stack
        for(int i = 0; i < list.length; i++) {
           this.push(list[i]);
        }
    }

    //Default Constructor
    public MyStack()
    {
       top = null;
        size = 0;
    }

    /* Function to check if stack is empty */
    public boolean isEmpty()
    {
        return top == null;
    }
    /* Function to get the size of the stack */
    public int getSize()
    {
        return size;
    }
    /* Function to push an element to the stack */
    public void push(String data)
    {
        Node nptr = new Node (data, null);
        if (top == null)
            top = nptr;
        else
        {
            nptr.setLink(top);
            top = nptr;
        }
        size++ ;
    }
    /* Function to pop an element from the stack */
    public String pop()
    {
        if (isEmpty() )
            throw new NoSuchElementException("Underflow Exception") ;
        Node ptr = top;
        top = ptr.getLink();
        size-- ;
        return ptr.getData();
    }

    /* Function to display the status of the stack */
    public void printStack()
    {
        System.out.print(" Stack = ");
        if (size == 0)
        {
            System.out.print("Empty ");
            return ;
        }
        Node ptr = top;
        while (ptr != null)
        {
            System.out.print(ptr.getData()+" ");
            ptr = ptr.getLink();
        }
        System.out.println();
    }
}

/* Class LinkedStackImplement */
public class StackImplementation
{

    public static void main(String[] args)
    {
       Scanner scan = new Scanner(System.in); //Creating a scanner object to take the input from the user
        /* Creating object of class linkedStack */
        MyStack ms = new MyStack();

        char ch;
        do
        {
            System.out.println(" Linked Stack Operations");
            System.out.println("1. push");
            System.out.println("2. pop");
            System.out.println("3. Check Empty");
            System.out.println("4. Print Stack");
            int choice = scan.nextInt();

            switch (choice)
            {
            case 1 :
                System.out.println("Enter a String element to push");
                String item = scan.next();
                ms.push(item);
                break;
            case 2 :
                try
                {
                    System.out.println("Popped Element = "+ ms.pop());
                }
                catch (Exception e)
                {
                    System.out.println("Error : " + e.getMessage());
                }
                break;
            case 3 :
                System.out.println("Empty status = "+ ms.isEmpty());
                break;
            case 4 :
                System.out.println("Stack = ");
                ms.printStack();
                break;
            default :
                System.out.println("Wrong Entry ");
                break;
            }

            System.out.println(" Do you want to continue (Type y or n) ");
            ch = scan.next().charAt(0);

        } while (ch == 'Y'|| ch == 'y');
    }
}

Sample Run:

Linked Stack Operations
1. push
2. pop
3. Check Empty
4. Print Stack
1
Enter a String element to push
Hello