面向對象的實例應用：圖形計算器

時間 2019-11-09

原文原文鏈接

1.使用動態頁面實現圖形計算器，能夠計算給定圖形的周長和麪積
2.可使用接口或抽象類做爲規範，再寫各子類的多態
3.動態頁面以下：php

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title></title>
        <style>
            #cal{
                text-align: center;
            }
        </style>
    </head>
    <body>
        <div id="cal">
            <h1>圖形計算器</h1>
            <a href="save.php?action=rect">矩形</a>||
            <a href="save.php?action=triangle">三角形</a>||
            <a href="save.php?action=cycle">圓形</a>
            <hr>
        </div>
        <?php
            include "get.php";
            if(!empty($_GET['action'])){
                $p=ucfirst($_GET['action']);
                $s=new $p($_POST);
                $s->input();
                
                if(!empty($_POST)){
                    if($s->identify($_POST)){
                        echo $s->name."的周長爲：".$s->getPerimeter()."<br>";
                        echo $s->name."的面積爲：".$s->getArea()."<br>";
                    }                        
                }
            
            }else{
                echo "請選擇圖形！<br>";
            }
            
        ?>
    </body>
</html>

4.接口與各子類以下：html

<?php    
    interface Calculate {
        function input();
        function getPerimeter();
        function getArea();
        function identify($arr);
    };
    class Triangle implements Calculate {
        private $line1;
        private $line2;
        private $line3;
        public $name;
        function __construct($arr){
            if(!empty($arr)){
                $this->line1=$arr['line1'];
                $this->line2=$arr['line2'];
                $this->line3=$arr['line3'];
                $this->name="三角形";
            }    
        }        
        function input(){
            if(!empty($_POST)){
                $line1=$_POST['line1'];
                $line2=$_POST['line2'];
                $line3=$_POST['line3'];
            }else{
                $line1=null;
                $line2=null;
                $line3=null;
            }
            $form="<form action='save.php?action=triangle' method='post'>";
            $form.="<label for='line1'>三角形第一條邊爲：</label><input type='text' id='line1' name='line1' value='".$line1."'/><br>";
            $form.="<label for='line2'>三角形第二條邊爲：</label><input type='text' id='line2' name='line2' value='".$line2."'/><br>";
            $form.="<label for='line3'>三角形第三條邊爲：</label><input type='text' id='line3' name='line3' value='".$line3."'/><br>";
            $form.="<button type='submit' name='doSubmit'>計算</button><br>";
            $form.="</form>";
            echo $form;
        }
        function getPerimeter(){
            return $this->line1+$this->line2+$this->line3;
        }
        function getArea(){
            $p=$this->getPerimeter()/2;
            return sqrt($p*($p-$this->line1)*($p-$this->line2)*($p-$this->line3));
        }
        function identify($arr){
            $line1=$arr['line1'];
            $line2=$arr['line2'];
            $line3=$arr['line3'];
            $identifier=true;
            if($line1<0){
                echo "第一條邊小於0<br>";
                $identifier=false;
            }
            if($line2<0){
                echo "第二條邊小於0<br>";
                $identifier=false;
            }
            if($line3<0){
                echo "第三條邊小於0<br>";
                $identifier=false;
            }
            if(($line1+$line2<$line3)||($line1+$line3<$line2)||($line2+$line3<$line1)){
                $identifier=false;
                echo "兩邊之和小於第三邊<br>";
            }
            return $identifier;
        }
    }
    class Cycle implements Calculate {
        private $radius;
        public $name;
        function __construct($arr){
            if(!empty($arr)){
                $this->radius=$arr['radius'];
                $this->name="圓形";
            }    
        }        
        function input(){
            $form="<form action='save.php?action=cycle' method='post'>";
            $form.="<label for='radius'>圓形的半徑爲：</label><input type='text' id='radius' name='radius'/><br>";
            $form.="<button type='submit' name='doSubmit'>計算</button><br>";
            $form.="</form>";
            echo $form;
        }
        function getPerimeter(){
            return 2*pi()*$this->radius;
        }
        function getArea(){
            return pi()*$this->radius*$this->radius;
        }
        function identify($arr){
            $identifier=true;
            if($arr['radius']<0){
                echo "半徑不能小於0！<br>";
                $identifier=false;
            }
            return $identifier;
        }
    }
    class Rect implements Calculate {
        private $height;
        private $width;
        public $name;
        function __construct($arr){
            if(!empty($arr)){
                $this->width=$arr['width'];
                $this->height=$arr['height'];
                $this->name="矩形";
            }    
        }
        function input(){
            $form="<form action='save.php?action=rect' method='post'>";
            $form.="<label for='width'>矩形的長度：</label><input type='text' id='width' name='width'/><br>";
            $form.="<label for='height'>矩形的寬度：</label><input type='text' id='height' name='height'/><br>";
            $form.="<button type='submit' name='doSubmit'>計算</button><br>";
            $form.="</form>";
            echo $form;
        }
        function getPerimeter(){
            return 2*($this->width+$this->height);
        }
        function getArea(){
            return $this->width*$this->height;
        }
        function identify($arr){
            $identifier=true;
            if($arr['width']<0){
                echo "寬度不能小於0！<br>";
                $identifier=false;
            }
            if($arr['height']<0){
                echo "高度不能小於0！<br>";
                $identifier=false;
            }
            return $identifier;
        }
    }
    
?>