Interface basics php oops

• By Admin
• Jan 05, 2019

In PHP, an interface is defined with “Interface“ keyword followed by the name of interface.

An interface can not contain “constant variables” as well as “normal variables” ( properties ).

All the methods which are declared in an “interface” must be “public”.

Only “Declaration” of “methods” are done in an “interface“.

All the methods must be implemented within a class.

The class which implements methods of the interface must have same signature of methods.

we can not create object of the interface.

An interface is a ‘pure abstract class’.

One interface can extends another interface.

Example 1:

<?php

	  /* interface A declaration */
	  interface A {
		
			public function Compute();
			
	  }
			
	 /* interface B extends interface A */
	 interface B extends A{
		
			/* member function declaration */
			public function Divide();
			
	  }
		
	 /* class C implements Class B */
	 class C implements B {
		
			/* function body */
			public function Divide() {
			
				$var = 10;
				$var1 = 2;
				$var3 = $var/$var1;
				echo 'division of 10/2 is'.' ' . $var3.'<br>';
				
			}
			
			/* function Body */
			public function Compute() {
			
				$a = 2;
				$b = 3;
				$c = $a*$b;
				echo 'multiplication of 2*3 is'.' ' . $c;
			
			}
		}
			
		$obj = new C();
		$obj->Divide();
		$obj->Compute();
			
?>

------------ ****** ------------

OUTPUT:
        division of 10/2 is 5.
        multiplication of 2*3 is 6.
		
		

Example 2:

<?php

		/* interface declaration */
		interface A {
		
			/* Member function declaration */
			public function setProperty($x);
			public function description();
			
		}
		interface B extends A {
		
		}
		
		/* Class Mangoes implements interface A */
		class Mangoes implements A{
		
			/* Member function */
			public function setProperty($x){
			
			  $this->x = $x;
			  
			}
			
			/* Member function */
			public function description(){
			
			  echo 'Describing' .' '. $this->x .' '.'tree';
			  
			}
		}
			
		$Mango = new Mangoes();
		$Mango->setProperty('mango');
		$Mango->description();
		
?>

------------ ****** ------------

OUTPUT:
         Describing mango tree.