Parameters and return values

Similar to other programming languages, parameters can be passed into functions in PHP, and functions can return results.

1. Function Parameters:

When we talk about parameters, when data is transferred by calling functions, it is therefore considered a method of passing argument.

Syntax:

function functionName($param1, $param2) {
    // Code using parameters
}

Example 1: Function with One Parameter

<?php
function greet($name) {
    echo "Hello, $name! Welcome to PHP.<br>";
}

// Calling function with arguments
greet("Alice");
greet("Bob");
?>

Explanation:

• Here $name is a parameter and the arguments passed were “Alice” and “Bob.”
• Output:
  • Hello, Alice! Welcome to PHP.
  • Hello, Bob! Welcome to PHP.

Example 2: Function with Multiple Parameters

<?php
function addNumbers($a, $b) {
    $sum = $a + $b;
    echo "The sum of $a and $b is: $sum <br>";
}

// Calling with different values
addNumbers(5, 10);
addNumbers(15, 25);
?>

Explanation:

• Output:
  • The sum of 5 and 10 is: 15
  • The sum of 15 and 25 is: 40

2. Default Parameter Values:

A default value should be given if no value is input

Example:

<?php
function greetUser($name = "Guest") {
    echo "Hello, $name!<br>";
}

greetUser("John"); // with argument
greetUser();       // without argument
?>

3. Return Values:

Sometimes, instead of printing inside the function, you want the function to give back a result. You do this with the return keyword.

Example 1: Returning a Value

<?php
function square($num) {
    return $num * $num;
}

$result = square(6);
echo "The square of 6 is: $result";
?>

Example 2: Returning Multiple Values via Array

<?php
function mathOperations($a, $b) {
    $sum = $a + $b;
    $product = $a * $b;
    return array($sum, $product);
}

list($s, $p) = mathOperations(5, 3);

echo "Sum = $s, Product = $p";
?>