How to define constants in PHP and access their values?

In PHP, you can define constants using the define() function and access their values using the constant name.

The syntax for defining constants is as follows:

Define a constant with a string constant name and any type of value.

For example, create a constant named PI with a value of 3.14.

Create a constant called “PI” and assign it the value of 3.14.

To access the value of a constant, you can simply use the constant name.

Set the variable piValue to the value of PI.

Note that constant names are case-sensitive.