Getting started with const in PHP

1. Do not want a member to be modified, you want the value to be constant

Attention:

The constant name does not precede the $

constants, when defined, need to be assigned an initial value and then cannot be changed

Does not require modifiers, the default public

2. Constants Assign initial values :

For example:

<?php

Class A

{

Const constant NAME = value;

}

Interface B

{

Const constant NAME = value;

}

?>

3. Access variables:

Class: Self:: constant name/class name:: Constant Name

Outside class: Class Name:: Constant Name

Case 1:

<?php

Class A

{

consttax_rate=123;//constants, when defined, need to be assigned an initial value, without the addition of modifiers, the default public

Public function Pay ($val)

{

return $val *a::tax_rate;

or return $val *self::tax_rate;

}

}

Interface B

{

Const xy=1234;

}

Class C implements B

{

Public Function Pay1 ($val)

{

return $val *b::xy;

}

}

$A 1=new A ();

The constant operation in the ECHO "class:". $A 1->pay (2);

ECHO "<BR>";

$C 1=new C ();

ECHO "The constant operation of the interface:". $C 1->pay1 (2);

ECHO "<BR>";

?>

Results :

Constant operations in the class: 246
Constant operation of the interface: 2468

This article is from "Uncle Wei Xiaobao" blog, please be sure to keep this source http://darmi.blog.51cto.com/11607923/1775271

Getting started with const in PHP