Question

Make sure you are using the appropriate indentation and styling conventions

Open the online API documentation for the ArrayList class, or the Rephactor Lists topic (or both). You may want to refer to these as you move forward.

Exercise 1 (15 Points)

• In BlueJ, create a new project called Lab7
• Create a class in that project called ListORama
• Write a static method in that class called makeLists that takes no parameters and returns no value
• In makeLists, create an ArrayList object called avengers that can hold String objects.

Exercise 2 (15 Points)

• Add the following names to the avengers list, one at a time:

Chris, Robert, Scarlett, Clark, Jeremy, Gwyneth, Mark

• Print the avengers object. You will notice that the contents are displayed in between two brackets [] and separated by a comma. This is how the toString() method of the ArrayList class is implemented!
• Then use a for-each loop to print each person in the list, one per line.

Exercise 3 (15 Points)

• Print a blank line.
• Print the current size of the ArrayList:

Current size of avengers: xxx

• Now use a regular for loop to print the elements of the list, one per line.

Exercise 4 (15 Points)

• Now remove the "Clark" and "Gwyneth" elements from the ArrayList. Remember, the list "closes the gaps" when something is removed.
• Print the current size again.

Now the size is: xxx

• Print the entire list object again.
• Make sure you removed the right people!

Exercise 5 (20 Points)

• Add "Chris H." to the end of the ArrayList.
• Change the first element "Chris" to "Chris E."
• Insert "Loki" between "Robert" and "Scarlett"
• Print the size of the ArrayList again.
• Print the entire list again.

Exercise 6 (20 Points)

• Print the elements of the ArrayList again, this time on one line separated by commas.
• Don't print a comma after the last name!
• To do this, use a regular for loop and the ArrayList get method to get each name to print.
• Use an if statement to decide whether to print a comma after each name

Answer 1

import java.util.ArrayList;
import java.util.List;

public class ListORama {
        private static List<String> avengers;
        public static void makeLists(){
                avengers=new ArrayList<String>();
        }
        public static void main(String[] args) {
                makeLists();
                avengers.add("Chris");
                avengers.add("Robert");
                avengers.add("Scarlett");
                avengers.add("Clark");
                avengers.add("Jeremy");
                avengers.add("Gwyneth");
                avengers.add("Mark");
                System.out.println(avengers.toString());
                for (String avenger : avengers) {
                        System.out.println(avenger);
                }
                System.out.println();
                System.out.println("Now the size is:"+avengers.size());
                for (int i = 0; i < avengers.size(); i++) {
                        String string = avengers.get(i);
                        System.out.println(string);
                        
                }
                avengers.remove("Clark");
                avengers.remove("Gwyneth");
                System.out.println("Now the size is:"+avengers.size());
                System.out.println(avengers.toString());
                avengers.add("Chris H");
                avengers.set(0, "Chris E.");
                avengers.add(avengers.indexOf("Robert")+1, "Loki");
                System.out.println("Now the size is:"+avengers.size());
                System.out.println(avengers.toString());
                for (int i = 0; i < avengers.size(); i++) {
                        String string = avengers.get(i);
                        if(i<avengers.size()-1)
                                System.out.print(string+",");
                        else
                                System.out.print(string);
                        
                }
                
        }
}