Php constructor and destructor

Php constructor and destructor

Php constructor is the first method automatically called after the object is created. destructor is the last method automatically called before the object is released. This article introduces php constructor and destructor.

Php Constructor

1. It is the "first" and "automatically called" method after the object is created.
2. Definition of constructor. The method name is fixed,

In php4: the same method as the class name is the constructor.
In php5: the constructor selects to use the magic method _ construct (). This name is used to declare constructor in all classes.

Advantage: you do not need to change the constructor when changing the class name.

Magic method: Write a magic method in the class, and the corresponding function of this method will be added
The method names are fixed (all provided by the system) and are not defined by the user.
Every magic method is automatically called to complete a function at different times.
Different magic methods have different call times.
All methods starting _
_ Construct (); _ destruct (); _ set ();......

Purpose: Initialize the member attributes;

Php destructor

1. The last method called automatically before the object is released
The garbage collector (java php) is used, and c ++ is manually released.
Purpose: close some resources for cleanup.

_ Destruct ();

Php constructor and destructor instance

Class Person {var $ name; var $ age; var $ sex; // constructor/* function Person () in php4 () {// each declared object calls echo "1111111111111111";} * // The constructor function _ construct ($ name, $ age, $ sex) in php5) {$ this-> name = $ name; $ this-> age = $ age; $ this-> sex = $ sex;} function say () {// $ this-> name; // use $ this echo for access by members in the object "my name: {$ this-> name}, my age: {$ this-> age} <br> "} function run () {} function eat () {}// destructor function _ destruct () {}}$ p1 = new Person ("zhangsan", 25, "male"); $ p2 = new Person; $ p3 = new Person;