Abstract, interface

<?php

/*class Ren {public static $color;   static function Show () {Ren:: $color;   Self:: $color;  }} class Car {public static $name;   }*//*/abstract class Dongwu {public $dong;      Public $jiao; function Chi () {} function Shui () {}}

Interface Extreme abstract class interface dongwu//definition interface, do not add class {} class Ren extends Dongwu {} $d = new ren*//*//interface keywords; interface The method inside the interface does not have the function body//implements the interface to use the keyword; implements, subclasses that do not use extends//implement interfaces must implement each method of the interface

 //Interface extremely abstract class  interface USB { function Read ()  {     }   function W Rite ()   {       }  }   //mouse  class Mouse extends USB  {  function Read ()   {   echo "inserted mouse";    }     function write ()    {    echo "Power you to Mouse";     }    }     //Keyboard   class Jianpan implements USB   {    function Read ()   {   echo "inserted mouse";    }    function Write () & nbsp;  {    echo "Power you to the mouse";     }         $m = new Mouse ();    $m->read ();    $m->write ();   */

Class Ren {public $name;  Public $sex;  Public $age;   function run () {} function Show () {echo ' name stands for name, sex representative, age, and the Run method represents the method of running;  }//destructor function __destruct () {//The memory is freed before the object is destroyed, the connection is closed, etc. echo "the object destroyed"; }//When the output object is called, there must be a return value to perform function __tostring () {//return "name for name, sex representative, age for ages, and run method to represent the method of running" return $this->   ; name; }}//Special: _destruct//Execution Time Special: Execute/* At time of object destruction * $r = new Ren (); $r->name = "Zhang San"; Var_dump ($R); */* $r = new Ren (); echo $r; * *

Small knowledge points

/* $a = 10; $b = 20; $c = 25; Unset ($b); if (Isset ($b)) {echo $a + $b, echo $a * $c, echo $sun, echo "<br>", Echo $a * $sum;}

if (Isset ($b)) {echo ' variable B does not exist! "; Exit ();//Quit the program die ("variable B does not exist!") ");//Output error message and exit program} Echo $a + $b; Echo $a * $c; Echo $sun; echo "<br>"; Echo $a * $sum;

$attr = Array (1,2,3,4); $a = "Hello"; Var_dump ($ATTR); Print_r ($ATTR); Print_r ($a); echo "Hello", "AA"; print "VV";

?>

Abstract, interface