PHP: Boolean Operators II

Derek Bridge

Department of Computer Science,
University College Cork

PHP: Boolean Operators II

Aims:

Class exercise

Short-circuit evaluation of && and ||

Short-circuit evaluation of &&

Boolean operators: !

Boolean operators: !

expr! expr
truefalse
falsetrue

See:

Boolean operators: !

Boolean expressions: precedence and associativity

Precedence and associativity of operators we have covered

OperatorPrecedenceAssociativity
(int), (float), (string), (bool), etc.highright
!right
*, /, %left
+, -, .left
<, <=, >, >=, <>n/a
==, !=, ===, !==n/a
&&left
||left
=right
andleft
orlowleft

Precedence and associativity of operators we have covered

Precedence and associativity of operators we have covered

Class exercise

Incomplete version of year.php

$year = (int) $_GET['year'];
    
$message = "<p>{$year} is not a leap year</p>";
if 
{
    $message = "<p>{$year} is a leap year</p>";
}
echo $message;