For each question, write the method assuming that it’s part of the StringArrayLi

Question

For each question, write the method assuming that it’s part of the StringArrayList we started in lecture.

A. (2 points) Write a public void set(int i, String s) method that sets the element of the list at index i to the value s. That is, it should overwritethe existing element at i. Be sure to handle exceptional conditions appropriately.

B. (2 points) Write a public int indexOf(String s) method that searches the list for the first occurrence of a value equivalent to s (be careful with what kind of equality you use!), and returns its index. Return -1 if the value is not found.

C. (1 point each) Suppose you instantiate a new StringArrayList. What are the size and the length of the backing array:

a) Right after instantiating the list.

b) After you add() 10 items to this list.

thank you!

c) After you remove(0) five times from this list.

Explanation / Answer

Java program:

import java.util.*;

public class StringArrayList

{

public static void main(String[]args)

{

ArrayList<String> list= new ArrayList<String>();

//Right after instantiating the list.

System.out.println("Size="+list.size());

//adding string elements to array list

list.add("First element");

list.add("Second element");

list.add("Third element");

//setting string at desired index- this is public void set(int i,String s) method

list.set(1, "Second-element replacement");

//public int indexOf(String s) method

int index=list.indexOf("Third element");

System.out.println("index="+index);

list.clear();//clearing operation in order to add ten elements to the list

//add() 10 items to the list

list.add("one");

list.add("two");

list.add("three");

list.add("four");

list.add("five");

list.add("six");

list.add("seven");

list.add("eight");

list.add("nine");

list.add("ten");

//Size after you add() 10 items to this list.

System.out.println("Size="+list.size());

//remove(0) five times from this list.

list.remove(0);

list.remove(0);

list.remove(0);

list.remove(0);

list.remove(0);

//Size after you remove(0) five times from this list.

System.out.println("Size="+list.size());

}

}

Output:

Size=0
index=2
Size=10
Size=5

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