JuniorTheoryCommon

What does the program print?

PHP

<?php

$yes = true;
$no = false;
$nothing = null;
echo '[', $yes, '][', $no, '][', $nothing, "]\n";

[1][][]

Expecting echo to print true, false and null by name: it prints each value as a string, which is '1' for true and empty for the other two.
Expecting false to print as 0: as a string false is empty, so a boolean you want to see on the screen goes through var_dump.

JuniorTheoryCommon

PHP

<?php

$yes = true;
$no = false;
$nothing = null;
echo '[', $yes, '][', $no, '][', $nothing, "]\n";

[1][][]

Expecting echo to print true, false and null by name: it prints each value as a string, which is '1' for true and empty for the other two.
Expecting false to print as 0: as a string false is empty, so a boolean you want to see on the screen goes through var_dump.