(Solved Homework): Add the following methods to the LinkedIntList : –size Returns size of the list.

import com.sun.xml.internal.bind.v2.model.core.ID;

//Class definition
public class LinkedListDemo
{
// create a Linked List class object
LinkedList list = new LinkedList();
//Method to return size
int size()
{
//Initialize the counter to zero
int count = 0;
//Creates an iterator
Iterator<String> itr = list.iterator();
//Moves till data available
while(itr.hasNext())
{
//Increase the counter by one
count++;
//Moves to next data
itr.next();
}//End of while
//Returns the counter
return count;
}//End of method

//Method to clear the list
void createList()
{
//To store data entered by the user
String data;
//Scanner class object created to accept data from the user
Scanner sc = new Scanner(System.in);
//Accept data till end entered by the user
System.out.println(“Enter string data to add to the list. Enter end to stop.”);
do
{
//Accept data
data = sc.next();
//Checks for end
if(data.equalsIgnoreCase(“end”))
//Come out of the loop
break;
else
//If not end then add it to the list
list.add(data);
}while(true);//End of while
}//End of method

//Method to return true if list is empty
boolean isEmpty()
{
//Initialize the counter to zero
int count = 0;
//Calls the size method and store the size in counter
count = size();
//Checks if the count is zero then return true
if(count == 0)
return true;
//Otherwise return false
else
return false;
}//End of method

//Method to clear all the data in the list
void clear()
{
//Calls the size method and store the size in c
int c = size();
//Loops till c
for(int i = 0; i < c; i++)
{
//removes the first element till condition becomes false
list.removeFirst();
}//End of for
}//End of method

//Overrides the toString method
public String toString()
{
//Initializes the result string to null
String result = “”;
//Creates an iterator class object
Iterator<String> itr = list.iterator();
//Moves till data available
while(itr.hasNext())
{
//Concatenates the data available in the list with the result
result += itr.next() + “, “;
}//End of while
//Return the result
return result;
}//End of method

//Returns the index position of the string given as parameter
int indexOf(String str)
{
//Initially ind is -1
int ind = -1;
//To store current string of the list
String current;
//Initializes the flag to -1 and counter to zero
int flag = -1, counter = 0;
//Creates an iterator class object
Iterator<String> itr = list.iterator();
//Moves till data available
while(itr.hasNext())
{
//Stores the current data from the list
current = itr.next();
//Increase the counter by one
counter++;
//Checks if the current item is equal to the string given as parameter (without considering the case)
if(current.equalsIgnoreCase(str))
{
//Set the flag value to the counter value
flag = counter;
//Come out of the loop
break;
}//End of if
}//End of while
//Returns the flag value
return flag;
}//End of method

//Return true if string is available otherwise false
boolean contains(String str)
{
//To store current string
String current;
//Initializes the flag to -1
int flag = -1;
//Creates an iterator class object
Iterator<String> itr = list.iterator();
//Moves till data available
while(itr.hasNext())
{
//Stores the current data from the list
current = itr.next();
//Checks if the current item is equal to the string given as parameter (without considering the case)
if(current.equalsIgnoreCase(str))
{
//Sets the flag to zero
flag = 0;
//Come out of the loop
break;
}//End of if
}//End of while
//Checks if the flag value is -1 return false
if(flag == -1)
return false;
//Otherwise return true
else
return true;
}//End of method

//Driver method
public static void main(String args[])
{
//To store string entered by the user
String data;
//Scanner class object created to accept data
Scanner sc = new Scanner(System.in);
//Creates LinkedListDemo class object
LinkedListDemo ld = new LinkedListDemo();
//Calls the method to add string to the list
ld.createList();
//Display the list using toString()
System.out.println(“List contents: ” + ld);
//Displays the size of the list
System.out.println(“Size: ” + ld.size());
//Displays the empty status
System.out.println(“Empty Status: ” + ld.isEmpty());

//Accepts a string to check the availability
System.out.println(“Enter a string to check exist or not: “);
data = sc.next();
//If returns true display available
if(ld.contains(data))
System.out.println(data + ” is available”);
//Otherwise display not available
else
System.out.println(data + ” is not available”);
//Accepts a string to display the index position
System.out.println(“Enter a string to find index position: “);
data = sc.next();
//Calls the method and stores the index position
int position =ld.indexOf(data);
//If the position is -1 display not available
if(position == -1)
System.out.println(data + ” is not available”);
//Otherwise display its index position
else
System.out.println(data + ” is available at ” + position);
//Clear the contents of the list
ld.clear();
//Display the size after clear
System.out.println(“After clear Size: ” + ld.size());
}//End of main
}//End of class

Output:

Enter string data to add to the list. Enter end to stop.
This
is
demo
end
List contents: This, is, demo,
Size: 3
Empty Status: false
Enter a string to check exist or not:
demo
demo is available
Enter a string to find index position:
is
is is available at 2
After clear Size: 0