| Mistake | Consequence | Fix | |---------|------------|-----| | (col % 2 == 0) only | Stripes, not checkerboard | Use (row + col) % 2 | | Using setFillColor instead of setColor | Square remains unfilled | Use setColor OR both setFilled(true) and setFillColor | | Forgetting setFilled(true) | Transparent squares | Add square.setFilled(true); | | Incorrect loop bounds (e.g., row <= ROWS ) | ArrayIndexOutOfBounds or extra row | Use < ROWS |
If you are still experiencing issues, it might be due to a specific world configuration in your CodeHS session. Double-check that your fillRow logic correctly handles the odd/even row requirement, as that is the most common cause of failure.
For an 8x8 grid, your program should print or store data that visualizes like this:
: Instead of wrapping back to the left wall every time, Karel moves across the board in a zigzag pattern (East-to-West, then West-to-East), which vastly reduces the total line count of your code. 916 checkerboard v1 codehs fixed
for (int row = 0; row < rows; row++) for (int col = 0; col < cols; col++) Color color = (row + col) % 2 == 0 ? Color.BLACK : Color.WHITE; g.setColor(color); g.fillRect(col * squareSize, row * squareSize, squareSize, squareSize);
: The board has gaps or extends beyond canvas boundaries.
This is the mathematical trick to the checkerboard pattern. for (int row = 0; row < rows;
A standard checkerboard requires Row 1 to start with a ball, while Row 2 must start with a blank space. If you use the exact same function for every row, your checkerboard will look like vertical stripes instead of a grid.
public static void main(String[] args) JFrame frame = new JFrame("Checkerboard"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.add(new Checkerboard()); frame.pack(); frame.setVisible(true);
while col_count > 0: # Draw Logic (simplified) t.penup() t.goto(x, y) t.pendown() t.begin_fill() # Draw square helper logic for i in range(4): t.forward(SIZE) t.left(90) t.end_fill() A standard checkerboard requires Row 1 to start
Many users encounter a "red" error in the autograder stating: "You should set some elements of your board to 1; You will need to use an assignment statement." . This occurs because:
# Inner loop for Columns for j in range(COLS):