Differences between new static () and new self (), staticself

Differences between new static () and new self (), staticself

Long night!

Today, leaders build a local site. It was found that PHP 5.2 could not be built, and the website PHP Code contains more than 5.3 of the content. The leaders forced me to run the changes under 5.2.

Changed and found a place

return new static($val);

This Nima is a magic horse. I have seen it before.

return new self($val);

So I checked the difference between them online.

Self-is the class in the code snippet.

Static-PHP 5.3 only adds the current class, which is a bit like $ this. It is extracted from the heap memory and accessed by the class currently instantiated, static indicates the class.

Let's take a look at the professional explanations of foreigners.

selfRefers to the same class whose methodnewOperation takes place in.

staticIn PHP 5.3's late static bindings refers to whatever class in the hierarchy which you call the method on.

In the following example,BInherits both methods fromA.selfIs boundABecause it's defined inA'S implementation of the first method, whereasstaticIs bound to the called class (also seeget_called_class() ).

class A {    public static function get_self() {        return new self();    }    public static function get_static() {        return new static();    }}class B extends A {}echo get_class(B::get_self());  // Aecho get_class(B::get_static()); // Becho get_class(A::get_static()); // A

You can understand this example.

I understand the principle, but the problem has not been solved. How can I solve the return new static ($ val) problem?

In fact, it is simple to use.Get_class ($ this); as follows

class A {    public function create1() {        $class = get_class($this);
　　　　return new $class();    }    public function create2() {        return new static();    }}class B extends A {}$b = new B();var_dump(get_class($b->create1()), get_class($b->create2()));/*The result string(1) "B"string(1) "B"*/

 

What is the difference between C ++ new and new?

Something is a little more. Haha. Let me explain it in detail.
1. Differences between new and new []
New is used to create a single object or instance, which is to call the class constructor.
New [] is used to create an array instance of an object or instance, and the address is continuous. (The memory allocation may be discontinuous, but the address linked list is continuous .)
2. virtual functions (this can't be said, just for example)
Class person
{
Public:
Virtual say ();
}
Class techer: public person
{
Public:
Protected override say ();
}
Class student: public person
{
Public:
Protected override say ();
}
The third one does not understand what it means.
The first two do not know what you understand. If not, contact me.

In JAVA, what is the static usage of static A = new? Details

In java
Public static void main (String args []) is a primary method,
Java programs can have multiple methods, but the main method can have only one,
The method modified with ststic is called a class method (main is also a class method ).
A a = new A () is A modifier used to create an instance object static.