The use of const keyword in PHP programs

Usage environment:

You can use define to define constants in PHP, but you cannot use define in classes. In classes, the values ​​of some attributes do not want to be modified. In this case, we need to use const to define them. constant.

Usage:

1. Member attributes modified with const are constants. In a class, const can only modify member properties.

2. It is recommended to use uppercase letters for constants. You cannot use $

3. The initial value of the constant must be given when it is declared

4. The access method of constants is the same as static, using ::, but Can only read

1. Use it outside the class class name::constant name

2. Use it inside the class self::constant name

The above introduces the use of the const keyword in PHP programs, including aspects of it. I hope it will be helpful to friends who are interested in PHP tutorials.