Unit 8: 2D Arrays

Homework

• Create a class for 2D array learning.
• Create a method to initialize a 2D array with arbitrary values
• Create a method to reverse the 2D array and print out the values
• Create a method that asks for the input of a position and it returns the corresponding value
• Create a method that multiplies each value in a row and then adds all the products together
• Create a new object to test out each method in the main function

import java.util.Scanner;
import java.util.Random;

public class Homework {

    int[][] numbers;

    public void printValues() { // arbitrary values
        for (int a = 0; a<numbers.length; a++) {
            for (int b = 0; b<numbers[a].length; b++) {
                numbers[a][b] = a + b; // spacing
                System.out.println(numbers[a][b] + " "); // spacing
            }
            System.out.println();
        }
    }

    public void reverseValues() {
        for (int a = numbers.length-1; a >= 0; a--) { // running for loop from ends of array
            for (int b = numbers[a].length-1; b >= 0; b--) {
                System.out.println(numbers[a][b] + " ");
            }
            System.out.println();
        }
    }

    public void findPosition() {
        Scanner scanner = new Scanner(System.in);

        System.out.println("Input row (0-2): ");
        int a = scanner.nextInt();
        System.out.println("Input column (0-2): ");
        int b = scanner.nextInt();

        System.out.println(numbers[a][b]);
    }

    public void mathNumbers() {
        int total = 0;

        for (int a = 0; a < numbers.length; a++) {
            int product = 1;
            for (int b = 0; b <numbers[a].length; b++) { // product of row
                product = product * numbers[a][b];
            }
            total += product;
        }
        System.out.println("Sum of row products: " + total);
    }

    public static void main(String[] args) {
        Homework homework = new Homework();
        homework.printValues();
        homework.reverseValues();
        homework.findPosition();
        homework.mathNumbers();
    }
}
Homework.main(null);

0 
1 
2 

1 
2 
3 

3 
2 
1 

2 
1 
0 

Input row (0-2): 
Input column (0-2): 
1
Sum of row products: 6