Challenge 2 — Solution

Task: Use a while loop to echo every even number from 2 to 20. Then
rewrite the same logic using continue inside a for loop that checks
every number from 1 to 20, skipping the odd ones.

<?php
    // while version
    $n = 2;
    while ($n <= 20) {
        echo "$n<br>";
        $n += 2;
    }

    echo "---<br>";

    // for + continue version
    for ($i = 1; $i <= 20; $i++) {
        if ($i % 2 !== 0) {
            continue;   // skip odd numbers entirely
        }
        echo "$i<br>";
    }
?>


Output:
2
4
6
...
20
---
2
4
6
...
20

Notes:
- The while version only ever touches even numbers directly, stepping
  by 2 each time ($n += 2), so there's nothing to skip.
- The for + continue version checks every number from 1 to 20, but
  continue immediately jumps to the next iteration whenever $i is odd
  (i % 2 !== 0), so only the even numbers ever reach the echo line.
- Both approaches produce the identical output, but they get there
  differently - one avoids generating odd numbers at all, the other
  generates every number and explicitly skips the ones it doesn't want.