Happy Coders

An interface is a blueprint that defines required methods without implementing them. A class that implements an interface must define all its methods. Interfaces allow multiple inheritance and help build loosely coupled, scalable systems. All interface methods must be public and cannot have bodies. Interfaces ensure consistency across different classes.

1. Basic Interface Example

interface Animal {
    public function makeSound();
}

class Dog implements Animal {
    public function makeSound() {
        return "Woof!";
    }
}

$dog = new Dog();
echo $dog->makeSound(); // Output: Woof!

File: interface_basic.php

2. Multiple Interfaces

interface A {
    public function methodA();
}

interface B {
    public function methodB();
}

class MyClass implements A, B {
    public function methodA() {
        return "A";
    }

    public function methodB() {
        return "B";
    }
}

$obj = new MyClass();
echo $obj->methodA(); // Output: A
echo $obj->methodB(); // Output: B

File: multiple_interfaces.php

3. Key Rules of Interfaces