PHP: 类继承-子类和父类同名方法会覆盖

类继承特性:

子类可以访问父类的成员，继承关键字extends，可以代码的重用性，子类中写了一个与父类同名的方法，这个方法会覆盖父类中的方法.
1)重用性
2)扩展性
3)灵活性

---

类继承

<?php
// Person.class.php

class Person{
	public $name;
	public $age;

	public function __construct($n,$a){
		$this->name=$n;
		$this->age=$a;
	}

	public function say(){
		echo "<p>my name is {$this->name}!</p>";
	}

	public function getAge(){
		echo "<p>my age is {$this->age}!</p>";
	}
}

class It extends Person{
    public $programme;

    public function __construct($n,$a,$p){
        parent::__construct($n,$a);

        $this->programme=$p;
    }

    public function develop(){
        echo "my programme is {$this->programme}";
    }
      
    }
$obj=new It('user123',19,'吹水');
$obj->say();
$obj->getAge();
$obj->develop();


?>

**

my name is user123!

my age is 19!
my programme is 吹水

---

子类和父类同名方法会覆盖

<?php
// Person.class.php

class Person{
	public $name;
	public $age;

	public function __construct($n,$a){
		$this->name=$n;
		$this->age=$a;
	}

	public function say(){
		echo "<p>my name is {$this->name}!</p>";
	}

	public function getAge(){
		echo "<p>my age is {$this->age}!</p>";
	}
}

class It extends Person{
    public $programme;

    public function __construct($n,$a,$p){
        parent::__construct($n,$a);

        $this->programme=$p;
    }

    public function develop(){
        echo "my programme is {$this->programme}";
    }
    public function say(){
		echo "<p>my name is {$this->name},my age is {$this->age},my programmer is {$this->programme}</p>";
	}
    }
$obj=new It('user123',19,'吹水');
$obj->say();



?>

**

my name is user123,my age is 19,my programmer is 吹水

---

**

**