916 Checkerboard V1 Codehs | Fixed

In this CodeHS JavaScript (Karel) exercise, you are instructed to create a checkerboard pattern on the screen. The pattern must:

public class Checkerboard extends ConsoleProgram public void run() // Example dimensions int rows = 5; int cols = 5; boolean[][] board = new boolean[rows][cols]; // Call the fixed method to populate the board createCheckerboard(board); // Print the board to verify the fix printBoard(board); public static void createCheckerboard(boolean[][] array) // array.length gives total rows for (int r = 0; r < array.length; r++) // array[r].length gives columns in that specific row for (int c = 0; c < array[r].length; c++) // Mathematical check for checkerboard positioning if ((r + c) % 2 == 0) array[r][c] = true; else array[r][c] = false; public static void printBoard(boolean[][] array) for (int r = 0; r < array.length; r++) for (int c = 0; c < array[r].length; c++) if (array[r][c]) System.out.print("[X]"); // Represents true / colored else System.out.print("[ ]"); // Represents false / empty System.out.println(); // Move to next line for the new row Use code with caution. Key Troubleshooting Tips for CodeHS Autograders

The most common "non-fixed" issues students encounter:

🚀 **CodeHS 9.1.6 Checkerboard v1: FIXED & WORKING!** 🚀 916 checkerboard v1 codehs fixed

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: Position calculations not resetting properly in nested loops.

board = [] # 1. Initialize an empty list for row in range(8): # 2. Outer loop for each of the 8 rows new_row = [] # 3. Create a new row list for col in range(8): # 4. Inner loop for the 8 columns if (row < 3 or row > 4): # 5. Check if we are in the top or bottom 3 rows # 6. Add a 1 if the sum of row and col is even, otherwise add a 0 new_row.append(1 if (row + col) % 2 == 0 else 0) else: new_row.append(0) # 7. For middle rows, add only zeros board.append(new_row) # 8. Append the completed row to the board In this CodeHS JavaScript (Karel) exercise, you are

# Add the row to the board board.append(current_row)

Using a simple boolean toggle (like isRed = !isRed ) at the end of the inner loop causes an error at the start of every new row. Because a standard checkerboard has an even number of columns, the last square of Row 1 and the first square of Row 2 end up being the exact same color, creating solid vertical stripes instead of a checkered pattern. 3. Loop Boundary Errors

After implementing the code above, run the program. You should see: Initialize an empty list for row in range(8): # 2

add(rect);

: Off-by-one errors in loop conditions or canvas size calculations.

Common bugs in Java include swapping the row and column boundaries ( array.length vs array[0].length ), which causes a ArrayIndexOutOfBoundsException on non-square grids. The Fixed Code

Before looking at the fixed code, it helps to understand why your current solution might be broken. Most student submissions fail due to three common logical errors: 1. The X and Y Coordinate Swap Students frequently mix up the pixel placement math. The coordinate depends on the column index, while the

: Ensure your row check is if row < 3 or row > 4: . If you use row <= 3 , you will incorrectly modify the 4th row.