Summary of several aspects of object-oriented inheritance in php

This article mainly summarizes several pointsphp object-orientedA few points when inheriting:

//people.class.php
	class People{
		private $name;
		private $sex;
		private $birthday;
		
		private function construct($name='',$sex='01',$birthday='1999-01-01'){
			echo &#39;people---construct<br>&#39;;
			$this->name = $name;
			$this->sex = $sex;
			$this->birthday = $birthday;
		}
		public function get($key){
			return $this->$key;
		}
		public function set($value,$key){
			$this->$key = $value;
		}
		public function show(){
			return &#39;people---&#39;;
		}
	}

//student.class.php
	class Student extends People{
		private $s_num;
		private $s_class;
		public function construct($name,$sex,$birthday,$num,$class){
			//parent::construct($name,$sex,$birthday);
			echo &#39;Student--construct<br>&#39;;
			$this->name = $name;
			$this->sex = $sex;
			$this->birthday = $birthday;
			$this->s_num = $num;
			$this->s_class = $class;
		}
		public function showInfo(){
			return &#39;sutdent---&#39;.$this->name.&#39;----bir=&#39;.$this->birthday
			.&#39;num==&#39;.$this->s_num.&#39;----class==&#39;.$this->s_class;
		}
	}

The above two classes Student inherit the People class

The constructor method of the parent class is private, which means in java This class cannot be inherited, but in php, this class can be inherited, but one thing is that the constructor of the parent class cannot be called in the subclass Student

parent::construct($name,$sex,$birthday);

Otherwise, an error will be reported, and if the constructor of the parent class is private, then the subclass must have its own constructor and must be written clearly, otherwise Inheritance is not possible.

At the same time, what is different from java is that when a subclass inherits a parent class and the subclass has its own constructor, the parent The constructor of a class will not be executed unless called from the constructor of a subclass.

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