Common and static properties in PHP

Normal Properties (instance properties):

the word for the instance is:instance

examples, in fact, also called "Object";

A normal (instance) attribute is a property that can be used on an object that is instantiated from that class!

definition form:

class name {

var $ Property name = initial value;

var $ property name; // This property has no initial value;

the above var can also be replaced with public , such as:

Public $ Property name = initial value;

Public $ Property name; // This property has no initial value;

}

form of Use:

Is through the object of the class to use the normal attribute (instance property):

$ Object , property name;

Because the nature of a property is a variable, it can be viewed and used as a variable, such as:

Property name $v 1 = $ Object ;

echo $ Object , property name;

$v 2 = $ Object , property name * 3 + 5; // calculation

Static properties:

A static property, which is essentially a "variable", has one characteristic: the variable is only subordinate to the "class", i.e.:

A static property in a class , only "One piece of data";

But:

An instance attribute in a class can have "multiple data"--each object is created with a copy of the data;

definition form:

class name {

Static $ Property name = initial value;

Static $ property name; // This property has no initial value;

}

form of Use:

use the class name and Range Resolver (::) to manipulate the static properties:

class Name:: $ static property name; // Note: property name with $ symbol

contrast 1:

Use of constants: Class Name:: Constant name;

contrast 2:

use of Instance properties: Object Name , instance property name; // Note: Property name does not have a $ symbol

The result is:

Visible:

1, the instance property, is each object can be different data, is also each object "own" the data;

2, static property, which he does not belong to any object, but belongs to the class itself, but also can be understood as a common data for all objects;

Common and static properties in PHP