PHP学习笔记06——面向对象版图形计算器

index.php　　用于显示页面

 1 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 2 <html>
 3     <head>
 4         <title>图形计算器</title>
 5     </head>
 6     <body>
 7         <center>
 8             <h1>图形(周长&面积)计算器</h1>
 9                 <a href = "index.php?action=rect">矩形</a>
10                 <a href = "index.php?action=circle">圆形</a>
11         </center>
12         <?php 
13             //错误级别设置为除了注意全部输出,避免输出变量未定义等消息
14             error_reporting(E_ALL & ~E_NOTICE);
15         
16             //使用自动加载类技术
17             function __autoload($className){
18                 include strtolower($className).".class.php";
19             }
20             
21             //实际是调用了Form类的__toString方法;
22             echo new Form("index.php");
23             
24             if(isset($_POST["sub"])) {
25                 echo new Result();
26             }
27         ?>
28     </body>
29 
30 
31 </html>

form.class.php　　根据action不同(rect,circle)显示不同的form

 1 <?php
 2     class Form {
 3         private $action;
 4         private $shape;
 5         
 6         function __construct($action = "") {
 7             $this->action = $action;
 8             //默认rect;
 9             $this->shape = isset($_GET['action']) ? $_GET['action'] : "rect";
10         }
11         
12         function __toString() {
13             $form = '<form action = "'.$this->action.'?action='.$this->shape.'" method="post">';
14             
15             //根据get请求组成方法名称字符串,例如GetRect()
16             $shape = "get".ucfirst($this->shape);
17             $form .= $this->$shape();
18             $form .= '<br/><input type="submit" name="sub" value="计算"><br/>';
19             $form .= '</form>';
20             return $form;
21         }
22         
23         private function getRect() {
24             $input = '<b>请输入 | 矩形  | 的宽度和高度: </b><p>';
25             $input .= '宽度: <input type="text" name="width" value="'.$_POST["width"].'"/><br/>'; 
26             $input .= '高度: <input type="text" name="height" value="'.$_POST["height"].'"/><br/>';
27             return $input;
28         }
29 
30         private function getCircle() {
31             $input = '<b>请输入 | 圆形  | 的半径: </b><p>';
32             $input .= '半径: <input type="text" name="radius" value="'.$_POST["radius"].'"/><br/>';
33             return $input;
34         }
35         
36     }
37 ?>

result.class.php　　根据action构造对应的类并输出结果

 1 <?php
 2     class Result {
 3         private $shape = null;
 4         //构造方法,根据action类新建类
 5         function __construct(){
 6             $this->shape = new $_GET['action']();
 7         }
 8         //利用多态性根据形状自动计算周长和面积
 9         function __toString(){
10             $result = $this->shape->shapeName.'的周长: '.round($this->shape->perimeter(), 2).'<br/>';
11             $result .= $this->shape->shapeName.'的面积: '.round($this->shape->area(), 2).'<br/>';
12             return $result;        
13         }
14     }
15 
16 ?>

shape.class.php　　图形的基类,定义了计算面积和周长的抽象方法

 1 <?php
 2     abstract class Shape {
 3         public $shapeName;
 4         //定义两个抽象方法,计算面积和周长
 5         abstract function area();
 6         abstract function perimeter();
 7         
 8         //验证数据合法性的方法
 9         protected function validate($value, $messgae = "输入值") {
10             if ($value==""||!is_numeric($value)||$value < 0) {
11                 $messgae = $this->shapeName.$messgae;
12                 echo '<font colr="red">'.$messgae.'不合法</font><br/>';
13                 return false;
14             }
15             return true;
16         }
17     }
18 
19 ?>

rect.class.php　　矩形的实现

 1 <?php
 2     class Rect extends Shape {
 3         private $width = 0;
 4         private $height = 0;
 5         function __construct(){
 6             $this->shapeName = "矩形";
 7             if ($this->validate($_POST["width"], "高度")&&$this->validate($_POST["height"], "宽度")) {
 8                 $this->width = $_POST["width"];
 9                 $this->height = $_POST["height"];
10             }
11         }
12 
13         public function area() {
14             return $this->width * $this->height;
15         }
16         public function perimeter() {
17             return 2 * ($this->width + $this->height);
18         }
19     }
20 ?>

circle.class.php　　圆形的实现

 1 <?php
 2     class Circle extends Shape {
 3         private $radius = 0;
 4         function __construct(){
 5             $this->shapeName = "圆形";
 6             if ($this->validate($_POST["radius"], "半径")) {
 7                 $this->radius = $_POST["radius"];
 8             }
 9         }
10 
11         public function area() {
12             return pi() * $this->radius * $this->radius;
13         }
14         public function perimeter() {
15             return 2 * pi() * $this->radius;
16         }
17     }
18 ?>

页面结果