该页面无法处理请求。运行 php 在本地主机上

Question

我是运行本地主机上的这段代码。在 http://localhost:8000/Polymorphism.php 上运行时出现错误。这是 php 上的简单多态代码。其他代码很容易运行但是有错误运行这段代码

此页面不工作本地主机当前无法处理此请求。 HTTP 错误 500

<?php


public interface Shape{

   public function calculateArea();


} 

 public class Circle implements Shape{

  private $radius;


  public function __construct($r){
   $this->radius=$r;
  }

  public function calculateArea(){

  echo 'Area of circle = '.pi()* $this->radius*$this->radius.'<br>';

  }
}

class Rectangle implements Shape{

 private $height;
 private $width;

 public function __construct($h,$w){
  this->height=$h;
  this->width=$w;
 }

 public function calculateArea(){
 echo 'Area of a Rectangle=' .$this->height.$this->width.'<br>';
 }

 }

 $circle= new Circle(5);
 $rect= new Rectangle(10,20);


 $circle->calculateArea();
 $rect->calculateArea();


?>

Answer 1

您永远不会将访问修饰符分配给 classes 或 interfaces.They 仅用于特定的方法和属性。你在 class Rectangle 中还有两个错误，你应该在

中提到高度和宽度

  $this->height=$h;
  $this->width=$w;

将您的整体代码更改为

<?php
interface Shape{

 public function calculateArea();

} 

class Circle implements Shape{

  private $radius;


  public function __construct($r){
   $this->radius=$r;
 }

 public function calculateArea(){

  echo 'Area of circle = '.pi()* $this->radius*$this->radius.'<br>';

}
}

class Rectangle implements Shape{

 private $height;
 private $width;

 public function __construct($h,$w){
  $this->height=$h;
  $this->width=$w;
}

public function calculateArea(){
 echo 'Area of a Rectangle=' .$this->height.$this->width.'<br>';
}

}

$circle= new Circle(5);
$rect= new Rectangle(10,20);

$circle->calculateArea();
$rect->calculateArea();
?>

该页面无法处理请求。运行 php 在本地主机上

The page is unable to handle request. running php on localhost

php

xampp

localhost

该页面无法处理请求。 运行 php 在本地主机上

The page is unable to handle request. running php on localhost

php

xampp

localhost

该页面无法处理请求。运行 php 在本地主机上