java,c#,php类与继承简单比较

简单比较 java,c#,php 创建类，继承，创建对象的异同点。

先简单用三种语言创建两个类Human，Singer,其中Singer继承Human。

相同点：

1可以使用继承，并且只能继承一个类，不能多重集成，但是接口可以多重继承其他接口。

2访问性，子类可以都可以访问父类的非私用属性和方法。

不同点：

1继承，java和php通过extends关键字表示继承，c#使用：表示；

2定义属性和方法，java和c#一样，php的属性和对象前都加上$字符前缀，如$name；使用function关键字定义方法；构造函数写法为：function __construct

3对象访问属性和方法，java和c#完全一样，创建对象和调用示范:

Singer s = new Singer("dd",166,110);

s.eat("苹果");

php属性通过->符号访问。 

$dd = new Singer("dd",166,110);

$dd->eat("橘子");

代码简单实现如下：

java代码：
public class Human{
  public string name;
  public int height;
  public int weight;
  public void eat(string food)
  {
　　system.out.println("eat"+food);
  }
}
public class Singer extends Human{//1
    public string songType;
    public Singer(string name,int height,int weight){
          this.name=name;
          this.height = height;
          this.weigh=weigh;
   }   
   public void singAsong(string songName){
      System.out.println("sing "+songName);
   }
}

 

c#代码：
public class Human{
  public string name;
  public int height;
  public int weight;
  public void eat(string food)
  {
　　 Console.WriteLine("eat"+food);
  }
}
public class Singer : Human{//1
    public string songType;
    public Singer(string name,int height,int weight){
          this.name=name;
          this.height = height;
          this.weigh=weigh;
   }
   public void singAsong(string songName){
      Console.WriteLine("sing "+songName);
   }
}

<?php
  class Human{
  public $name;
  public $height;
  public $weight;
  public function eat($food)
  {
　　echo $this->name." like eat".$food;
  }
}
 class Singer extends Human{//1
    public  $songType;
    function __construct($name,$height,$weight){
          $this->name=$name;
          $this->height = $height;
          $this->weigh=$weigh;
   }
   public function singAsong($songName){
      echo $this->name." is sing ".$songName;
   }
}
?>