What is the difference between inheriting classes and implementing interfaces in php

The difference between inherited classes and implemented interfaces in PHP: 1. PHP inheritance belongs to single inheritance, which ensures unity, but is not flexible enough. Implementing interfaces is a supplement to single inheritance; 2. Implementing interfaces can be done in different places. Expand the functionality of a certain class without destroying the hierarchical relationship.

The operating environment of this tutorial: Windows 10 system, PHP version 7.1, DELL G3 computer

The difference between inherited classes and implemented interfaces in php

1. Comparison between inheritance and interface implementation:

(1) PHP inheritance belongs to single inheritance, which ensures unity, but is not flexible enough. Implementing interfaces is a supplement to single inheritance;

(2) Implementing interfaces can extend the functionality of a certain class without destroying the class hierarchical relationship.

"; } } interface iBirdable { public function fly(); } interface iFishable { public function swimming(); } class LittleMonkey extends Monkey implements iBirdable,iFishable { public function fly() { echo "猴子还会飞
"; } public function swimming() { echo "猴子也会游泳
"; } } $littleMonkey = new LittleMonkey(); $littleMonkey -> climbing(); $littleMonkey -> fly(); $littleMonkey -> swimming(); ?>

2. Final keyword:

1. If a class does not want to be inherited by other classes (from a security perspective), it can be modified with final;

2 . If you hope that a certain method cannot be overridden by subclasses (you do not want the method to be overloaded by subclass methods), you can also use final modification.

getRate(100)."
"; ?>

3. Final cannot modify member variables (properties).

3. const:

1. When an attribute does not want to be modified, you can consider using const to make it a constant. For example, pi cannot be tampered with.

2. Basic syntax:

const constant name = assign initial value;

If you do not assign an initial value, it cannot be tampered with later and it will not have a value.

3. Modifiers cannot be written on constants. They default to public but cannot be written out.

4. Constant names are generally named in all capital letters.

5. Calling syntax:

Used inside the class:

self::constant name or class name::constant name;

in External use of the class:

Interface name::constant;

Recommended learning: "PHP Video Tutorial"

The above is the detailed content of What is the difference between inheriting classes and implementing interfaces in php. For more information, please follow other related articles on the PHP Chinese website!