How to declare functions in PHP?

Steps to declare a function in PHP: Use the function keyword to declare a function. Specify parameters after the function name, separated by commas. Use a colon and type to specify the return type (optional). Write the code to be executed in the function body. Returns a value (optional).

#How to declare a function in PHP?

A function is a reusable block of code that performs a specific task and returns a result. In PHP, functions are declared using the function keyword.

Function declaration syntax:

function functionName(parameter1, parameter2, ...) {
    // 函数体
}

Parameters:

A function can accept zero or more parameters. Parameters are the data passed to the function.

Function body:

The function body contains the code to be executed.

Return type:

The function can return a value or not. To specify a return type, use a colon (:) after the function name, and then specify the type. For example:

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

Practical case:

The following is a practical case of declaring a function in PHP and using it:

<?php

// 声明一个返回两个数字之和的函数
function sum(int $a, int $b): int {
    return $a + $b;
}

// 使用此函数
$result = sum(10, 20);

// 打印结果
echo "The sum is: $result";
?>

Output:

The sum is: 30

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