A few years ago, a paragraph of the general content is that the wife called the programmer husband to say that he would buy 10 buns on the way, and if he saw a watermelon, he would buy one. As a result, the programmer husband bought a steamed stuffed bun and went home.

Recently I saw it on the internet. It's a sudden fantasy. I wrote a PHP program and restored the whole process with the program.

I. File directory structure
-/ App - Project Root Directory
-/ Buyer - Executor, here we simulate two people, a programmer, an editor, and others.
        -/Coder.php
        -/Editor.php
-/Boss.php - demand side (wife adults)
-/ Buy.php - Buy (or replace it with other operations)
-/ Loader.php - Automatic loading class
-/index.php - entry file

Two, code

1.index.php

<?php

define('BASEDIR', __DIR__);

include BASEDIR.'/App/Loader.php';
spl_autoload_register("\\App\\Loader::autoload");

//$buyer ='Coder'; // Programmer
$buyer = 'Editor'; // edit
$boss = new App\Boss();
$boss->callBuyer($buyer); // Call buyer
$boss->getBaoZi(); // Buy some steamed buns

2.Loader.php

<?php

namespace App;

class Loader
{
    public static function autoload($class)
    {
        //var_dump($class);
        $file = BASEDIR.'/'.str_replace('\\', '/', $class).'.php';
        //echo $file;
        include $file;
    }
}

3.Buy.php

<?php

namespace App;

class Buy
{
    public $baoZiNum = 0; // Number of stuffed bun
    public $xiGuaNum = 0; // Watermelon number
    public $flag = true; // true: There are watermelon sellers, false: there are no watermelon sellers.

    public function __construct()
    {
        echo "Yes, let me do something.\n";
    }

    public function getBaoZi()
    {}
}

4.Boss.php

<?php

namespace App;

class Boss
{
    public static $obj;

    public function callBuyer($user)
    {
        echo "Call $user . . . \n";
        $class = "\\App\\Buyer\\".$user;
        $userObj = new $class;
        self::$obj = $userObj;
    }

    public function getBaoZi()
    {
        echo "Buy 10 steamed buns back. If you sell watermelon, buy one.\n";
        self::$obj->getBaoZi();
        $baoZi = self::$obj->baoZiNum;
        $xiGua = self::$obj->xiGuaNum;
        echo "I came back and bought it. $baoZi A steamed stuffed bun. $xiGua A watermelon.\n";
    }
}

5.Coder.php

<?php

namespace App\Buyer;

use App\Buy;

class Coder extends Buy
{

    public function getBaoZi()
    {
        $this->baoZiNum = 10; // Ten steamed buns to buy
        if($this->flag){ // There are watermelon sellers.
            $this->baoZiNum = 1; // Buy one
        }
    }
}

6.Editor.php

<?php

namespace App\Buyer;

use App\Buy;

class Editor extends Buy
{

    public function getBaoZi()
    {
        $this->baoZiNum = 10; // Buy 10 steamed buns
        if($this->flag){ // There are watermelon sellers.
            $this->xiGuaNum = 1; // Buy a watermelon
        }
    }
}