效果：
index.php
<!DOCTYPE html>
<html>
<head>
<title>图形计算（使用面向对象技术开发）</title>
<meta http-equiv="content" content="text/html" charset="utf-8" />
</head>
<body>
<center> <!--居中-->
<h1>图形（周长&面积）计算器</h1>
<!--计算图形的链接-->
<a href="index.php?action=rect">矩形</a>||
<a href="index.php?action=triangle">三角形</a>||
<a href="index.php?action=circle">圆形</a>
<hr> <!--创建一条水平分隔线-->
</center>
<?php
//错误报告处理
//error_reporting(E_ALL & ~E_NOTUCE);
//自动加载需要的类文件
function __autoload($className){
//strtolower()函数，把类名转化为小写
include strtolower($className).".class.php";
}
echo new Form();
if(isset($_POST["sub"])){
echo new Result();
}
?>
</body>
</html>
form.class.php
<?php
class Form{
private $action;
private $shape;
//在PHP5中的构造方法
function __construct($action=""){
$this->action=$action;
$this->shape=isset($_REQUEST["action"])?$_REQUEST["action"]:"rect";
}
//在直接输出对象引用的时候自动调用
function __toString(){
$form='<form action="'.$this->action.'" method="post">';
//echo $this->shape;
switch($this->shape){
case "rect":
//要加到表单里面，要返回字符串
$form.=$this->getRect();
break;
case "triangle":
$form.=$this->getTriangle();
break;
case "circle":
$form.=$this->getCircle();
break;
default:
$form.='请选择一个形状<br>';
}
$form.='<input type="submit" name="sub" value="计算">';
$form.='</form>';
return $form;
}
//得到矩形的方法
private function getRect(){
$input='<b>请输入矩形的宽度和高度：</b><p>';
$input.='宽度：<input type="text" name="width" value="'.$_POST["width"].'"><br>';
$input.='高度：<input type="text" name="height" value="'.$_POST["height"].'"><br>';
$input.='<input type="hidden" name="action" value="rect">';
return $input;
}
//得到三角形的方法
private function getTriangle(){
$input='<b>请输入三角形的三条边：</b><p>';
$input.='第一条边：<input type="text" name="side1" value="'.$_POST["side1"].'"><br>';
$input.='第二条边：<input type="text" name="side2" value="'.$_POST["side2"].'"><br>';
$input.='第三条边：<input type="text" name="side3" value="'.$_POST["side3"].'"><br>';
$input.='<input type="hidden" name="action" value="triangle">';
return $input;
}
//得到圆形的方法
private function getCircle(){
$input='<b>请输入圆形的半径：</b><p>';
$input.='半径：<input type="text" name="radius" value="'.$POST["radius"].'"><br>';
$input.='<input type="hidden" name="action" value="circle">';
return $input;
}
}
?>
shape.class.php
<?php
abstract class Shape{
public $shapeName;
abstract function area();
abstract function perimeter();
//验证
protected function validate($value,$message="形状"){
if($value==""||!is_numeric($value)||$value<0){
echo '<font color="red">'.$message.'必须为非负值的数字，并且不能为空！</font><br>';
return false;
}else{
return true;
}
}
}
?>
result.class.php
<?php
class Result{
private $shape;
function __construct(){
switch ($_POST['action']) {
case 'rect':
$this->shape=new Rect();
break;
case 'triangle':
$this->shape=new Triangle();
break;
case 'circle':
$this->shape=new Circle();
break;
default:
$this->shape=false;
break;
}
}
//在直接输出对象引用的时候自动调用
function __toString(){
if($this->shape){
$result=$this->shape->shapeName."的周长：".$this->shape->perimeter().'<br>';
$result.=$this->shape->shapeName."的面积：".$this->shape->area().'<br>';
return $result;
}else{
return "没有这个形状<br>";
}
}
}
?>
Rect.class.php
<?php
class Rect extends Shape{
private $width=0;
private $height=0;
function __construct(){
$this->shapeName="矩形";
if($this->validate($_POST["width"],'矩形的宽') & $this->validate($_POST["height"],"矩形的长")){
$this->width=$_POST["width"];
$this->height=$_POST["height"];
}else{
exit;
}
}
//面积
function area(){
return $this->width*$this->height;
}
//周长
function perimeter(){
return 2*($this->width+$this->height);
}
}
?>
Triangle.class.php
<?php
class Triangle extends Shape{
private $side1=0;
private $side2=0;
private $side3=0;
function __construct(){
$this->shapeName="三角形";
if($this->validate($_POST["side1"],'三角形的第一条边') & $this->validate($_POST["side2"],"三角形的第二条边") & $this->validate($_POST["side3"],"三角形的第三条边")){
$this->side1=$_POST["side1"];
$this->side2=$_POST["side2"];
$this->side3=$_POST["side3"];
if(!$this->validateSum()){
echo '<font color="red">三角形的两边之和必须大于第三边！</font><br>';
exit;
}
}else{
exit;
}
}
//海伦公式
function area(){
$s=($this->side1+$this->side2+$this->side3)/2;
return sqrt($s*($s-$this->side1)*($s-$this->side2)*($s-$this->side3));
}
function perimeter(){
return $this->side1+$this->side2+$this->side3;
}
//验证两边之和大于第三边
private function validateSum(){
$condition1=($this->side1 + $this->side2)> $this->side3;
$condition2=($this->side1 + $this->side3)>$this->side2;
$condition3=($this->side2 + $this->side3)>$this->side1;
if($condition1 & $condition2 & $condition3){
return true;
}else{
return false;
}
}
}
?>
Circle.class.php
<?php
class Circle extends Shape{
private $radius=0;
function __construct(){
$this->shapeName="圆形";
if($this->validate($_POST["radius"],'圆的半径')){
$this->radius=$_POST["radius"];
}else{
exit;
}
}
function area(){
return pi()*$this->radius*$this->radius;
}
function perimeter(){
return 2*pi()*$this->radius;
}
}
?>