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);   }}

     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;   }}?>