Day 4 - Decision Making - Become PHP Expert in 30 days

[admin]

http://php.flashwebhost.com/sherly/numbers1.php

<?php
if ($a > $b) {
  echo "a is greater than b";
} else {
  echo "a is NOT greater than b";
}

Where did this $a and $b comes from ? have you assigned any value ? i don't see it in code.