9.1.7 Checkerboard V2 Answers May 2026

Even with the correct code, students often hit frustrating roadblocks. Here’s a quick troubleshooting table:

A: The GraphicsProgram class has its own main method internally. You do not need to write public static void main . Just extend GraphicsProgram .

private static final int NUM_ROWS = 8; private static final int NUM_COLS = 8; private static final int SQUARE_SIZE = 50; // Pixels per square 9.1.7 checkerboard v2 answers

A: Check your x and y calculations. x = col * size ensures the first column starts at 0. If you accidentally add an offset, correct it.

A: No. Some versions of 9.1.7 use black and gray. If the sample image shows gray, replace Color.RED with Color.GRAY . Even with the correct code, students often hit

import acm.graphics.*; import acm.program.*; import java.awt.*; public class Checkerboard extends GraphicsProgram

If you've landed on this article, you're likely working through the CodeHS Java course (specifically the "Methods and Control Structures" or "Basic Java" units) and have hit the infamous 9.1.7 Checkerboard v2 exercise. Don't worry—you're not alone. This problem is a rite of passage for learning nested loops, modulus logic, and graphical user interface (GUI) manipulation in Java. Just extend GraphicsProgram

public void run() // Loop through each row for (int row = 0; row < NUM_ROWS; row++) // Loop through each column in the current row for (int col = 0; col < NUM_COLS; col++) // Calculate the x and y coordinates for this square int x = col * SQUARE_SIZE; int y = row * SQUARE_SIZE; // Create a new GRect (square) GRect square = new GRect(x, y, SQUARE_SIZE, SQUARE_SIZE); square.setFilled(true); // Determine the color based on the checkerboard pattern // Even sum starts with RED at (0,0) if ((row + col) % 2 == 0) square.setColor(Color.RED); else square.setColor(Color.BLACK); // Add the square to the canvas add(square);