How to define a function in php

The format of functions defined in PHP is: function function_name(parameters) {//Function body}

##Defined in PHP Function

Definition format:

<code class="php">function function_name(parameters) {
    // 函数体
}</code>

Description:

##function_name
• : Function name, consisting of letters, numbers or underscores, and cannot start with numbers.
parameters
• : Optional, list of parameters received by the function. Each parameter consists of its type and name, separated by commas.
Function body
• : Contains the code to be executed by the function.

Example:

<code class="php">// 无参函数
function hello() {
    echo "Hello, world!";
}

// 有参函数
function sum(int $a, int $b) {
    return $a + $b;
}</code>

Rules:

Function names must be unique.

• The parameter type and number must be consistent with the function definition.
• Code in the function body can access variables outside the function, but cannot modify them.
• A function can return a value using the
return
• statement.

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