Exercise 4: Checkerboard

Create and print a 4×4 checkerboard pattern:

B W B W
W B W B
B W B W
W B W B

Starter Code

for r in range(4):
    for c in range(4):
        if ___:
            print("B", end=" ")
        else:
            print("W", end=" ")
    print()

Hints

Hint 1 — Look at the pattern

Notice that B appears when (row + col) is even, and W when it's odd:

(0,0) = 0+0 = 0 (even) → B
(0,1) = 0+1 = 1 (odd) → W
(1,0) = 1+0 = 1 (odd) → W
(1,1) = 1+1 = 2 (even) → B

Hint 2 — How to check even/odd?

Use the modulo operator %. A number is even when number % 2 == 0.

if (r + c) % 2 == 0:

Bonus Challenge

Make it any size! Ask the user for the number of rows and columns:

rows = int(input("Rows: "))
cols = int(input("Cols: "))
# Print the checkerboard

Solution

Show Solution

for r in range(4):
    for c in range(4):
        if (r + c) % 2 == 0:
            print("B", end=" ")
        else:
            print("W", end=" ")
    print()

How it works:

For each position, add the row and column numbers
If the sum is even → print B
If the sum is odd → print W
The % 2 == 0 check tells us if a number is even

Show Bonus Solution

rows = int(input("Rows: "))
cols = int(input("Cols: "))

for r in range(rows):
    for c in range(cols):
        if (r + c) % 2 == 0:
            print("B", end=" ")
        else:
            print("W", end=" ")
    print()

Checkerboard

Exercise 4: Checkerboard

Starter Code

Hints

Bonus Challenge

Solution

Try it yourself

Code: Checkerboard