Example analysis of how to call abstract methods in php

Abstract method refers to a method that only has a method name but no implementation. This method must be implemented through a subclass. In PHP, abstract methods are defined using the abstract keyword. When a class contains one or more abstract methods, the class must be declared as abstract.

In PHP, calling abstract methods is the same as calling ordinary methods. The abstract method can be called by implementing the abstract method in the parent class through the subclass. Here is an example:

abstract class Animal {
    abstract function makeSound();
}

class Dog extends Animal {
    function makeSound() {
        echo "汪汪<br>";
    }
}

class Cat extends Animal {
    function makeSound() {
        echo "喵喵<br>";
    }
}

$dog = new Dog();
$dog->makeSound();  // 输出 "汪汪"

$cat = new Cat();
$cat->makeSound();  // 输出 "喵喵"

In the above example, we define an abstract class Animal, which contains an abstract method makeSound(). Then we defined two subclasses Dog and Cat respectively, and rewritten the makeSound() method in the Animal class respectively.

Finally, we create an instance of the Dog class $dog and an instance of the Cat class $cat, and call their respective makeSound() methods.

It should be noted that if a class contains one or more abstract methods, then the class must be declared as an abstract class. Abstract classes cannot be instantiated and can only be used as parent classes, which are inherited by subclasses and implement the abstract methods in them.

If a subclass inherits an abstract class, then the subclass must implement all abstract methods in the abstract class, otherwise the subclass must also be defined as an abstract class.

In PHP, abstract methods are a very useful method, which allows parent classes to define some basic methods that must be implemented, and subclasses can implement these methods according to their own needs. In this way, we can define some common methods in the parent class to avoid repeatedly writing the same code in each subclass, improving the reusability and maintainability of the code.

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