PHP class and constructor parsing

About the class we all have a certain understanding here only in PHP class noteworthy places

The creation of----class----

PHP uses the keyword class to create a class and uses a pair of curly braces
Such as:

Class name{public  $n = "";  Private $u = "";  Public Function name () {    $n = "233";    $u = "23333";  }  Public function Rename ($newn) {     $this->n= $newn;//this represents this class  }}

The end does not score the number. $n, $u is a field; name () is a constructor (__construct () can also define a constructor, as described below), you can assign a value to a field; Rename () is a method.

----field----

Comparison
$obj =new name ();
Echo $obj->n;
And
$obj =new name ();
Echo $obj->u;

The former can be executed, and the latter cannot be declared private before $u. This is similar to C + +.

Code:

public static $nm = "2333333333333333";

A static field is declared for the function.
Through the class name and:: You can access the variable directly

echo Name:: $nm;

This is similar to C + +.

In PHP, you can also access static fields in a class by self::+$+ variable names, where self is equivalent to $this->.

The use of methods is similar to fields

----constructor----

Constructors have the same name as classes in PHP5 and earlier versions

In PHP5 and later versions, the magic word __construct () can define constructors

Magic word __construct () to define constructors

Class name{public  $n = "";  Private $u = "";  Public Function __construct () {    $n = "233";    $u = "23333";  }  Public function Rename ($newn) {     $this->n= $newn;  }}

Constructors can have parameters

__construct ($name = "", $sex = "man", $age =0) {}

When declaring an object

$obj = new name ("I", "man", 28);

If no argument is given, the default is = after value.