Question

In java, request and read in 10 integers from the terminal and put into an ArrayList. Remember, an ArrayList can only store object references, so you will need to take advantage of autoboxing.

Then add the numbers together that have been placed in the array, first with the use of an iterator, and then with an enhanced for loop, printing out the results in each case.

Answer 1

//TestCode.java

import java.util.ArrayList;
import java.util.Iterator;
import java.util.Scanner;

public class TestCode {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        ArrayList<Integer> arrayList = new ArrayList<>();

        System.out.println("Enter 10 numbers");
        for (int i = 0; i < 10; i++) {
            arrayList.add(scan.nextInt());
        }

        int sum1 = 0;
        Iterator<Integer> iter = arrayList.iterator();
        while (iter.hasNext()) {
            sum1 += iter.next();
        }
        System.out.println("Sum using iterator: " + sum1);

        int sum2 = 0;
        for (int x : arrayList) {
            sum2 += x;
        }
        System.out.println("Sum using enhanced for: " + sum2);
    }
}

Output:

Enter 10 numbers Sum using iterator: 49 Sum using enhanced for: 49