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PHP implements Keyword

❮ PHP Keywords


Implement an interface:

interface Machine {
  public function activate();
  public function deactivate();
  public function isActive();

class Kettle implements Machine {
  private $isOn = false;

  public function activate() {
    $this->isOn = true;

  public function deactivate() {
    $this->isOn = false;

  public function isActive() {
    return $this->isOn;

$machine = new Kettle();

if($machine->isActive()) {
  echo "The machine is on";
} else {
  echo "The machine is off";

echo "<br>";
if($machine->isActive()) {
  echo "The machine is on";
} else {
  echo "The machine is off";
Try it Yourself »

Definition and Usage

The implements keyword is used to declare that a class must have the methods described in the specified interface. This is called polymorphism. Polymorphism makes it easy to use a variety of different objects in the same way.

Related Pages

The interface keyword

The else keyword

Read more about objects, classes and interfaces in our PHP OOP Tutorial.

❮ PHP Keywords