Syntax and usage of PHP functions

PHP functions are reusable blocks of code that receive arguments, perform operations, and return output. Function syntax: function function_name(parameter1, parameter2, ...) { // Function body return $output;}. Functions can receive any parameters (optional type) and can return any type of value (default is void). Functions can be used to: break down tasks, handle exceptions, and avoid duplication.

PHP Functions: Syntax and Usage Guide

A function is a reusable block of code that accepts incoming parameters and performs operations. and return the output. The syntax of functions in PHP is simple:

function function_name(parameter1, parameter2, ...) {
  // 函数体
  return $output;
}

Parameters

A function can accept any number of parameters separated by commas. Both parameter names and types can be specified in the function signature:

function add_numbers(int $num1, int $num2): int {
  return $num1 + $num2;
}

Return value

A function can return a value of any type using the return statement. If the return value type is not specified, it will return void by default:

function double_value($num) {
  return $num * 2; // 返回 int 类型
}

Practical case

Let us consider a method that calculates the sum of two numbers Function:

<?php
function sum_numbers($num1, $num2) {
  $sum = $num1 + $num2;
  return $sum;
}

// 调用函数
$result = sum_numbers(5, 10);

// 输出结果
echo "结果：$result";
?>

In this example, the sum_numbers function receives two numbers as arguments, calculates their sum and returns the result. The echo statement is used to print the results to the screen.

Other uses

Function can also be used for:

• Decompose complex tasks
• Handle exceptions
• Avoid code duplication

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