What are the components of a PHP function?

PHP function consists of function header, function parameters, function body and return value: function header contains function name, parameter list and optional return value type. Function parameters are variables passed into the function. The function body executes the code to be executed. A function can return a value via the return statement, the type of which is optionally specified in the function header.

Parts of a PHP function

A PHP function is a predefined block of code that performs a specific task. It consists of the following components:

1. Function header

The function header specifies the name, parameter list and return value type of the function (optional):

function function_name(argument1, argument2, ...): return_type {
    // 函数体
}

For example:

function greet(string $name): string {
    return "Hello, $name!";
}

2. Function parameters

Function parameters are variables or values ​​that are passed to the function. They are specified in the function header, and the type and name are optional.

3. Function body

The function body contains the code to be executed. It is located between the function header and the curly braces {}.

4. Return value

The function can return a value, specified by the return statement. The return type is specified in the function header (optional).

Practical case

Consider a function that calculates the sum of two numbers:

function sum(int $a, int $b): int {
    return $a + $b;
}

// 调用函数
$result = sum(10, 20);
echo $result; // 输出: 30

Notes

• Function names are size-sensitive in PHP Write.
• The type and name of the parameters are optional but critical to the robustness and readability of the code.
• If a function does not explicitly declare a return value type, it will return void (None) by default.

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