$2$

$.$

$$Modify the

$$

LinkedStackOfStrings

$.$

java

$$

$$program given in the textbook

$($

program

$4$

$.$

$3$

$.$

$2$

$)$

$$by adding a method

$$

find

$($

$)$

$$

$$that takes a string as an argument. It should return true if the string argument is in the linked stack and false otherwise.

$[$

MO

$6$

$.$

$1$

$]$

$$

The main method should also be modified so that all the strings

$($

other than the search string

$)$

$$inputted by the user are stored on the stack before calling the find

$($

$)$

$$method$.$

Sample runs would be as follows.

$$

$>$

java LinkedStackOfStrings hello

this

is a

test run

for the

hello program

$$

hello exists in the linked stack

Program

$4$

$.$

$3$

$.$

$2$

$$

public class LinkedStackOfString

$\{$

$$

$$ private Node first;

$$private class Node

$\{$

$$

$$ private String item;

$$ private Node next;

$$

$\}$

$$

$$public boolean isEmpty

$($

$)$

$\{$

$$

$$ return

$($

first

$=$

$=$

$$null

$)$

;

$$

$\}$

$$

$$public void push

$($

String item

$)$

$\{$

$$

$$ Node oldFirst

$=$

$$first;

$$ first

$=$

$$new Node

$($

$)$

;

$$ first.item

$=$

$$item;

$$ first.next

$=$

$$oldFirst;

$$

$\}$

$$

$$public String pop

$($

$)$

$\{$

$$

String item

$=$

$$first$.$item;

first

$=$

$$first$.$next;

return item;

$$

$\}$

$$

public boolean find

$($

String searchItem

$)$

$\{$

$$

Node current

$=$

$$first;

$$ while

$($

current

$!$

$=$

$$null

$)$

$\{$

$$

$$ if

$($

current

$.$

item.equals

$($

searchItem

$)$

$)$

$\{$

$$

$$ return true;

$\}$

$$

$$ current

$=$

$$current$.$next;

$\}$

$$

$$ return false;

$\}$