The strlen() function is a built-in PHP function. It counts the number of characters in a string.
The text is: Hello World
The number of characters is: 11
The addNumbers() function is a function created by the programmer. It takes two numbers, adds them together, and returns the result.
10 + 5 = 15
Functions are reusable sections of PHP code that perform a particular task. PHP has built-in functions that are already available for programmers to use. Programmers can also create user-defined functions for tasks they need. Functions can receive information through parameters and can return a result. Using functions helps organize code and prevents the same code from being written repeatedly.