Type declarations for parameters in PHP - Mini Project: Build & Apply

Type Declarations for Parameters in PHP

📖 Scenario: You are building a simple calculator that adds two numbers. To make sure the calculator works correctly, you want to tell PHP exactly what kind of values the calculator should accept.

🎯 Goal: Create a PHP function that adds two numbers using type declarations for the parameters to ensure only numbers are accepted.

📋 What You'll Learn

Create a function named addNumbers with two parameters named $a and $b.

Use type declarations to specify that both $a and $b must be integers.

Call the function with two integer values.

Print the result of the function call.

💡 Why This Matters

🌍 Real World

Type declarations help prevent errors by making sure functions get the right kind of data, which is important in real-world applications like calculators, data processing, and web forms.

💼 Career

Understanding type declarations is useful for writing clear, reliable PHP code, a skill valued in web development jobs.

1

Create the function skeleton

Write a function named addNumbers that takes two parameters named $a and $b without type declarations yet.

PHP

<?php

// Define the function addNumbers with parameters $a and $b
function addNumbers($a, $b) {
    // Your code here
}

Need a hint?

Use the function keyword followed by the function name and parentheses with parameters.

2

Add type declarations to parameters

Modify the addNumbers function to add type declarations so that both parameters $a and $b are declared as int.

PHP

<?php

// Add type declarations to parameters $a and $b
function addNumbers(int $a, int $b) {
    // Your code here
}

Need a hint?

Put int before each parameter name inside the parentheses.

3

Add the function logic

Inside the addNumbers function, write code to return the sum of $a and $b.

PHP

<?php

function addNumbers(int $a, int $b) {
    // Return the sum of $a and $b
    // Your code here
}

Need a hint?

Use the return keyword followed by $a + $b.

4

Call the function and print the result

Call the addNumbers function with the integers 5 and 7, store the result in a variable named $result, and print $result.

PHP

<?php

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

// Call addNumbers with 5 and 7, store in $result
// Print $result
// Your code here

Need a hint?

Use $result = addNumbers(5, 7); and then print($result);.