Function Parameters Return Values | Functions

Introduction

Functions are a fundamental part of PHP programming. They help in organizing code into reusable blocks. In this tutorial, we will explore function parameters and return values in PHP.

Function Parameters

Function parameters are variables that are passed to a function when it is called. They allow functions to receive input values and use them within the function body. Here's a simple example:

<?php
function greet($name) {
    echo "Hello, " . $name . "!";
}

greet("Alice");
greet("Bob");
?>

In this example, the greet function takes one parameter, $name. When the function is called with greet("Alice"), it outputs "Hello, Alice!". Similarly, greet("Bob") outputs "Hello, Bob!".

Default Parameters

PHP allows you to define default values for function parameters. If a parameter is not provided when the function is called, the default value will be used. Here's an example:

<?php
function greet($name = "Guest") {
    echo "Hello, " . $name . "!";
}

greet();
greet("Alice");
?>

In this example, the greet function has a default parameter value of "Guest". If greet() is called without any arguments, it outputs "Hello, Guest!". If greet("Alice") is called, it outputs "Hello, Alice!".

Return Values

Functions can return values using the return statement. The returned value can be stored in a variable or used directly. Here's an example:

<?php
function add($a, $b) {
    return $a + $b;
}

$result = add(5, 3);
echo $result; // Outputs: 8
?>

In this example, the add function takes two parameters, $a and $b, adds them together, and returns the result. The returned value is then stored in the $result variable and printed.

Returning Multiple Values

PHP does not support returning multiple values directly. However, you can return an array containing multiple values. Here's an example:

<?php
function calculate($a, $b) {
    $sum = $a + $b;
    $difference = $a - $b;
    return array($sum, $difference);
}

list($sum, $difference) = calculate(5, 3);
echo "Sum: " . $sum . ", Difference: " . $difference;
?>

In this example, the calculate function returns an array containing the sum and difference of the input values. The list function is used to assign the returned values to individual variables.

Type Declarations

PHP 7 introduced type declarations for function parameters and return values. You can specify the expected data type for parameters and the return type of a function. Here's an example:

<?php
function add(int $a, int $b): int {
    return $a + $b;
}

echo add(5, 3); // Outputs: 8
?>

In this example, the add function specifies that both parameters must be integers and the return value must also be an integer.

Conclusion

Understanding function parameters and return values is essential for writing efficient and reusable code in PHP. Parameters allow functions to receive input values, while return values enable functions to produce and return results. With the addition of type declarations in PHP 7, you can now write more robust and predictable code.

Function Parameters and Return Values in PHP

Introduction