


Detailed explanation of php class constant definition and examples
What are class constants?
In php, we can understand that a quantity whose value does not change is called a constant. So, what is a class constant? In fact, class constants are also easy to understand. We can call the value that always remains unchanged in the class a constant, and this constant can be called a class constant. Be sure to remember that you do not need to use the "$" symbol when defining and using constants.
Class constants belong to the class itself, not to object instances, and cannot be accessed through object instances
* Cannot be modified with public, protected, private, static
* Subclasses can be repeated To write constants in the parent class, you can call the constants in the parent class through (parent::)
* Since PHP5.3.0, you can use a variable to dynamically call the class. But the value of this variable cannot be a keyword (such as self, parent or static).
Definition of class constants
Class constants are defined using the const keyword:
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Example
Define and use a class constant
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Code running result:
Result In the above example, we use the subclass to rewrite the parent class constant, the code is as follows :
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Code running results:
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Detailed explanation of the definition and usage examples of PHP constants
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