Instance usage of Class constant in object-oriented of PHP
This article mainly introduces "PHP object-oriented instance usage of class constants", in daily operation, I believe many people in PHP object-oriented instance usage of class constants have doubts, Xiaobian consulted all kinds of information, sorted out simple and easy to use operation methods, hope to answer "PHP object-oriented instance usage of class constants" doubts helpful! Next, please follow the small series to learn together!
Class constant is a very important concept in PHP object-oriented programming. A firm grasp of class constant helps to further improve the level of PHP object-oriented programming. This article describes the use of class constants in PHP programming as an example. The details are as follows:
Class Constant: Class in which constant data is stored during the running cycle.
Definition:
const keyword const constant name = constant value
Examples are as follows:
class Student{public $stu_id;public $stu_name;public $stu_gender;const GENDER_MALE ='male '; const GENDER_FEMALE ='female';}
Class constants are not restricted by access qualifiers
Access method:
class:: constant name
Examples are as follows:
class Student{public $stu_id;public $stu_name;public $stu_gender;const GENDER_MALE ='male '; const GENDER_FEMALE ='female'; public function __construct($id,$name,$gender=''){$this->stu_id= $id;$this->stu_name= $name;$this->gender= ($gender =='')? self::GENDER_MALE : $gender;}}
Summary: The members that can be defined in a class are: constants, static attributes, non-static attributes, static methods, and non-static methods.
Note here:
$this represents the current object, so does it always represent the object of the class in which $this is located?
The answer is no! Because the value of $this does not depend on the class in which $this is located, but on the execution object (execution environment) when the method in which $this is located is called
The execution environment of the method. The $this in the method indicates which object the current method is executed in.
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