Challenge 3 — Solution

Task: Write a function censorWord($sentence, $word) that uses
str_replace() to replace every occurrence of $word in $sentence with
asterisks matching its length (e.g. "cat" becomes "***"). Test it on a
sentence containing the target word twice.

<?php
    function censorWord($sentence, $word) {
        $mask = str_repeat("*", strlen($word));
        return str_replace($word, $mask, $sentence);
    }

    $sentence = "The cat chased the other cat up the tree.";
    echo censorWord($sentence, "cat");
?>


Output:
The *** chased the other *** up the tree.

Notes:
- str_repeat("*", strlen($word)) builds a mask of asterisks exactly as
  long as the word being censored, so "cat" (3 letters) becomes "***"
  automatically, without hardcoding the number of asterisks.
- str_replace() replaces every occurrence of $word in $sentence, not
  just the first one - both instances of "cat" are masked in a single
  call.
- Because the function takes $word as a parameter rather than
  hardcoding "cat", censorWord() can reuse the identical logic to
  censor any word passed in.