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JavaScript while Loop — exercises and bug fixes

5 hands-on exercises and 5 find-the-bug challenges for the JavaScript while Loop lesson. Every one is checked automatically in the browser — write the code, run it, and the tests tell you what still fails.

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Exercises(5)

  1. 1

    Count to four

    easy10 min

    Use a while loop to count 1,2,3,4 and join them with commas.

  2. 2

    Halve until small

    easy10 min

    Starting at 40, halve repeatedly while above 5, then show the value.

  3. 3

    Sum while under a limit

    easy10 min

    Add 1,2,3... while the running total stays below 10, then show the total.

  4. 4

    Drain a list

    easy10 min

    Remove items from [1,2,3] until it is empty, then show the count removed.

  5. 5

    Find the first multiple

    medium10 min

    Find the first number above 10 divisible by 7.

Find the bug(5)

  1. 1

    Fix the condition that never runs

    easy8 min

    The comparison points the wrong way, so the loop body is skipped.

  2. 2

    Fix the wrong start value

    easy8 min

    The counter starts too high, so the first numbers are missing.

  3. 3

    Fix the counter that moves the wrong way

    easy8 min

    Decrementing means the loop exits immediately.

  4. 4

    Fix the wrong divisor test

    easy8 min

    This searches for a multiple of the wrong number.

  5. 5

    Fix the emptied list check

    easy8 min

    The loop checks the wrong end condition and removes nothing.

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