Input:
Students new to coding can sometimes get stuck on this exercise. Here are the most common mistakes and how to fix them:
This article provides a complete walkthrough of the problem, the conceptual understanding needed to solve it, the correct code structure, and debugging tips for the CodeHS autograder. 1. Understanding the Challenge 9.1.6 checkerboard v1 codehs
Once you have mastered 9.1.6 Checkerboard v1 , challenge yourself with these modifications:
Used to detect if a sum of indices is even or odd ( ), which helps determine where to place a '1'. Input: Students new to coding can sometimes get
The prompt for this exercise typically reads something like this:
: Since the CodeHS canvas is 400 pixels wide and you need 8 circles, each "cell" is 50 pixels wide. The radius must be 25 . Understanding the Challenge Once you have mastered 9
function main() while (leftIsClear()) fillRow(); repositionToNextRow(); // Fill the very last row fillRow(); // Fills a row with the checkerboard pattern function fillRow() while (frontIsClear()) putBeeper(); if (frontIsClear()) move(); if (frontIsClear()) move(); putBeeper(); // Moves Karel up and aligns to the next row function repositionToNextRow() if (facingEast()) if (leftIsClear()) turnLeft(); move(); turnLeft(); else if (rightIsClear()) turnRight(); move(); turnRight(); // Helper to turn right function turnRight() turnLeft(); turnLeft(); turnLeft(); Use code with caution. 4. Detailed Explanation of the Code main() Function
A loop that repeats the setup and move functions until the top of the world is reached. 3. The 9.1.6 Checkerboard V1 Code Solution
Try implementing this yourself using the logic above. If you get stuck, ask your teacher or a classmate for help — working through the logic is how you learn best!
The outer for loop begins at r = 0 . Before it moves to r = 1 , the inner for loop executes completely from c = 0 to c = 7 . This draws the first horizontal row of the board from left to right. The process repeats for all 8 rows. The Modulo Condition