Note:Unlike other object-oriented Programming LanguageIn PHP, the class cannot use the final modifier for an attribute variable.
If you want to declare an attribute as a constant, you can use the const keyword, without using the dollar symbol as the variable name prefix or access permission modifier. A constant means that although the variable can be accessed, the value of the variable cannot be modified. For example CodeDeclared the constant attribute con_var:
Copy codeThe Code is as follows: <? PHP
Class Foo {
Const con_var = "the value of the constant attribute cannot be modified <br/> ";
Public Function method_a (){
Echo (SELF: con_var );
}
}
Echo (FOO: con_var );
$ Myfoo = new Foo ();
Echo ($ myfoo-> method_a ());
?>
Constant attributes cannot be accessed by objects. They can only be accessed by classes. In the class body, you can use "SELF: constant name" and use "Class Name :: constant name ".
