PHP Functions

The real power of PHP comes from its functions.

PHP has more than 1000 built-in functions, and in addition you can create your own constructor functions.

User Defined Functions

A user-defined function declaration starts with the word function:

function functionName() {
  code to be executed;
}

Note: A function name must start with a letter or an underscore. Function names are NOT case-sensitive.

PHP Function Arguments

Information can be passed to functions through arguments. An argument is just like a variable.

PHP Strict Types

In PHP 7, type declarations were added. This gives us an option to specify the data type expected when declaring a function, and by adding the strict_types declaration, it will throw a "Fatal Error" if the data type mismatches.