PHP Constants Example

Examples of Constants

The value of Pi is: 3.14159
The greeting message is: Hello, World!
The circumference of a circle with radius 5 is: 31.4159

Explanation of Constants

In PHP, constants are identifiers (names) for simple values. They are defined using the define() function, and once set, their values cannot be changed during the script’s execution. Unlike variables, constants do not require the dollar sign ($) prefix.

Constants are useful when you need a value that will remain the same throughout the script. For example, PI is a constant representing the mathematical constant for Pi, which will always remain the same. In contrast, variables can be changed during script execution and are typically used for storing dynamic values.