$*$I just need MyStack.java and Main.java$**$

$*$MyStack$.$java$*$

import java.util.NoSuchElementException;

public class MyStack implements IStack $\{$

$//$ add any necessary variables here

@Override

public void push$($Object item$)\{$

$\}$

@Override

public Object pop$()\{$

$\}$

@Override

public Object peek$()\{$

$\}$

@Override

public int indexOf$($Object item$)\{$

$\}$

@Override

public int size$()\{$

$\}$

@Override

public boolean isEmpty$()\{$

$\}$

$//$ add any necessary methods or classes below

$\}$

$*$IStack$.$java$**$

$/**$

A stack is a last in first out $($LIFO$)$ data structure.

New items are pushed onto the top of the list.

Items are popped from the top of the list.

$*/$

public interface IStack $\{$

$/**$

Pushes an item onto the top of this stack.

$*/$

public void push$($Object item$)$;

$/**$

Removes the object at the top of this stack and returns that object as the value of this function.

@return the item at the top of the stack or throws a NoSuchElementException is the stack is empty

$*/$

public Object pop$()$;

$/**$

Looks at the object at the top of this stack without removing it from the stack.

@return the item at the top of the stack or throws a NoSuchElementException is the stack is empty

$*/$

public Object peek$()$;

$/**$

searches the stack for an item.

@return the zero$-$based index of the item in the stack; returns $-1$ if the item is not in the stack.

$*/$

public int indexOf$($Object item$)$;

$/**$

A count of the number of items in the stack.

@return A count of the number of items in the stack.

$*/$

public int size$()$;

$/**$

Tests if this stack is empty.

@return true if the stack is empty

$*/$

public boolean isEmpty$()$;

$\}$

$**$Main$.$java$**$

$//$ you may use this file to write and run code to test your code

public class Main $\{$

public static void main$($String$[]$ args$)\{$

$\}$

$\}$

Structure of the Fields

While there are no required fields for your MyStack class, you will need to decide what fields to implement. This decision will be largely based on your choice to implement this MyStack as either an array list or a linked list.

Structure of the Methods

As described by the UML Class Diagram above, your MyStack class must implement the following methods:

a public method named push that takes an Object argument and returns nothing

a public method named pop that takes no arguments and returns an Object

a public method named peek that takes no arguments and returns an Object

a public method named indexOf that takes an Object argument and returns an int

a public method named size that takes no arguments and returns an int

a public method named isEmpty that takes no arguments and returns an boolean

Note that:

these methods are declared in the IStack interface. You will be implementing these methods in this MyStack concrete class.

Additional Information

MyStack

This concrete class will store its elements in either an internal array list or linked list. All such implementation details must be contained in your myStack.java file. You may add any additional fields, methods, and inner classes that you will need to achieve this.

push method

Add a new item to top of the stack. For example: given the stack $\{1,2,3\}($where the value $1$ is on the top$)$ and an instruction to push$(99),$ the result would be this $\{99,1,2,3\},$ with the value $99$ now on the top of the stack.

pop method

Remove and return the item currently on the top of the stack. For example: given the stack $\{1,2,3\}($where the value $1$ is on the top$)$ and an instruction to pop$(),$ the stack would now look like this $\{2,3\},$ and the value $1$ would be returned.

Throws a NoSuchElementException if the stack is currently empty when this method is called.

peek method

Return $($but do not remove$)$ the item currently on the top of the stack. For example: given the stack $\{1,2,3\}($where the value $1$ is on the top$)$ and an instruction to peek$(),$ the stack would still look like this $\{1,2,3\},$ and the value $1$ would be returned.

Throws a NoSuchElementException if the stack is currently empty when this method is called.

indexOf method

Return the $($zero$-$based$)$ number of elements from the front or top of the collection where the specified item is first found. Returns $-1$ if the item is not found in the collection. For example: given the stack $\{1,2,3\}($where the value $1$ is on the top$)$ and the instruction indexOf$(2),$ the value $1$ would be returned $($because the value $2$ was found at index $1(1$ element below the top$)$ in the stack. For another example: given the stack $\{1,2,3\}($where the value $1$ is on the top$)$ and the instruction indexOf$(99),$ the value $-1$ would be returned $($because the value $99$ is not found in the stack$).$

size method

Returns the number of elements currently stored in the stack.

isEmpty method

Returns true if there are currently no items stored in this stack, otherwise returns false.