1 exercise
The bool type (short for boolean) has only two values -- true and false.
The true and false literal values are case insensitive in code.
<?php
$value_is_true = true;
$value_is_false = false;
Boolean values are often use in logical expressions as the result of an operator and then used in control structures.
There are several logical operators:
!$a: returns true if $a is not true
$a && $b: returns true if $a and $b are both true
$a || $b: returns true if either $a or $b are true
There is an and and or operator and they are complementary to && and || respectively.
They do not have the same behaviour as && and || and may produce unexpected results, and as such their use is discouraged.
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Learn Booleans