Variables Examples

<?php
$x=5;
$y=6;
$z=$x+$y;
echo $z;
?>

Example

<?php
$txt="Hello world!";
$x=5;
$y=10.5;
?>

Example

<?php
$x=5; // global scope

function myTest()
{
$y=10; // local scope
echo "<p>Test variables inside the function:<p>";
echo "Variable x is: $x";
echo "<br>";
echo "Variable y is: $y";
}

myTest();

echo "<p>Test variables outside the function:<p>";
echo "Variable x is: $x";
echo "<br>";
echo "Variable y is: $y";
?>

PHP The global Keyword

The global keyword is used to access a global variable from within a function.

To do this, use the global keyword before the variables (inside the function):

Example

<?php
$x=5;
$y=10;

function myTest()
{
global $x,$y;
$y=$x+$y;
}

myTest();
echo $y; // outputs 15
?>

Example

<?php
$x=5;
$y=10;

function myTest()
{
$GLOBALS['y']=$GLOBALS['x']+$GLOBALS['y'];
}

myTest();
echo $y; // outputs 15
?>

Example

<?php

function myTest()
{
static $x=0;
echo $x;
$x++;
}

myTest();
myTest();
myTest();

?>

Example

<?php
$txt1="Learn PHP";
$txt2="W3Schools.com";
$cars=array("Volvo","BMW","Toyota");

print $txt1;
print "<br>";
print "Study PHP at $txt2";
print "My car is a {$cars[0]}";
?>

Example

<?php
$x = 5985;
var_dump($x);
echo "<br>";
$x = -345; // negative number
var_dump($x);
echo "<br>";
$x = 0x8C; // hexadecimal number
var_dump($x);
echo "<br>";
$x = 047; // octal number
var_dump($x);
?>

Example

<?php
$x = 10.365;
var_dump($x);
echo "<br>";
$x = 2.4e3;
var_dump($x);
echo "<br>";
$x = 8E-5;
var_dump($x);
?>

Example

<?php
class Car
{
  var $color;
  function Car($color="green")
  {
    $this->color = $color;
  }
  function what_color()
  {
    return $this->color;
  }
}
?>

Example

<?php
define("GREETING", "Welcome to W3Schools.com!", true);
echo greeting;
?>

Output:

Welcome to W3Schools.com! Welcome to W3Schools.com