PHP 抽象类

抽象类是接口和类的混合体。它可以定义功能以及接口。

• 扩展抽象类的类必须实现抽象类中定义的所有抽象方法。
• 抽象类的声明方式与普通类相同，只是添加了’abstract’关键字。

语法

abstract class MyAbstract
{
    //Methods
}
//And is attached to a class using the extends keyword.
class Myclass extends MyAbstract
{
    //class methods
}

示例1

<?php
abstract class a
{
abstract public function dis1();
abstract public function dis2();
}
class b extends a
{
public function dis1()
    {
        echo "javatpoint";
    }
    public function dis2()
    {
        echo "SSSIT";   
    }
}
obj = new b();obj->dis1();
$obj->dis2();
?>

输出：

示例2

<?php
abstract class Animal
{
    public name;
    publicage;
public function Describe()
        {
                return this->name . ", " .this->age . " years old";    
        }
abstract public function Greet();
    }
class Dog extends Animal
{
public function Greet()
        {
                return "Woof!";    
        }

        public function Describe()
        {
                return parent::Describe() . ", and I'm a dog!";    
        }
}
animal = new Dog();animal->name = "Bob";
animal->age = 7;
echoanimal->Describe();
echo $animal->Greet();
?>

输出：