What are the two types of php functions?

#php functions are divided into two types: built-in functions and custom functions.

Recommended reading: php server

##Built-in functions

So-called PHP built-in functions are functions that have been defined in the library of the PHP program, such as echo, mysql_connect, include_once, etc., just like the system functions in VC, such as cout, etc.

In PHP, more than 1,000 built-in functions are provided.

Custom functions

In addition to the built-in PHP functions, we can create our own functions.

• Function is a reusable code block used to complete a specific task in the program;

• Function can make the program more Modular, with good structure;

• After the function is defined, it can be called repeatedly in the program;

• The function will not be executed immediately when the page is loaded. .

• Function will only be executed when called.

Creating user-defined functions in PHP:

User-defined function declarations starting with the word "function":

Syntax

function functionname(){
    被执行的代码；
}

Note: Function names can start with letters or underscores (not numbers). Function names are not case sensitive.

Tip: The function name should reflect the task performed by the function.

Example:

We create a function named "shili()". An opening brace ({) indicates the beginning of a function's code, while a closing brace (}) indicates the end of the function. This function outputs "Hello world!". To call this function, just use the function name:

<?php
function shili()
{
    each"hello world!";
}
shili();
?>

Output:

hello world!

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