Why strict typing matters in PHP - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to enable strict typing in PHP.

PHP

<?php
[1]

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

echo add(5, 10);

Drag options to blanks, or click blank then click option'

Adeclare(strict_types=1);

Bstrict_types=1;

Cenable_strict();

Duse strict;

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to add the declare statement.

Using incorrect syntax like 'strict_types=1;' without declare.

Trying to enable strict typing with a function call.

In PHP, to enable strict typing, you must add declare(strict_types=1); at the top of the file.

2fill in blank

medium

Complete the function call to cause a type error when strict typing is enabled.

PHP

<?php
declare(strict_types=1);

function multiply(int $x, int $y): int {
    return $x * $y;
}

// This will cause a type error
$result = multiply([1], 5);
echo $result;

Drag options to blanks, or click blank then click option'

Anull

B10

C5

D"10"

Attempts:

3 left

💡 Hint

Common Mistakes

Passing an integer which is allowed.

Passing null which causes a different error.

Passing a number without quotes which is correct.

When strict typing is enabled, passing a string like "10" to a function expecting an int causes a type error.

3fill in blank

hard

Fix the error by completing the function parameter type declaration.

PHP

<?php
declare(strict_types=1);

function greet([1] $name): string {
    return "Hello, $name!";
}

echo greet("Alice");

Drag options to blanks, or click blank then click option'

Abool

Bint

Cstring

Darray

Attempts:

3 left

💡 Hint

Common Mistakes

Using int or bool which are wrong types for a name.

Not specifying any type which disables strict typing benefits.

The function expects a string parameter for the name. Using string as the type fixes the error.

4fill in blank

hard

Fill both blanks to create a function that returns the sum only if both inputs are integers.

PHP

<?php
declare(strict_types=1);

function safeAdd([1] $a, [2] $b): int {
    return $a + $b;
}

echo safeAdd(3, 7);

Drag options to blanks, or click blank then click option'

Aint

Bstring

Cfloat

Dbool

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing types like int and string.

Using float or bool which are not integers.

Both parameters must be typed as int to ensure strict typing and correct addition.

5fill in blank

hard

Fill all three blanks to create a function that returns the uppercase version of a string if it is not empty.

PHP

<?php
declare(strict_types=1);

function shout([1] $text): string {
    if ($text [2] '') {
        return strtoupper([3]);
    }
    return '';
}

echo shout('hello');

Drag options to blanks, or click blank then click option'

Astring

B!==

C$text

D===

Attempts:

3 left

💡 Hint

Common Mistakes

Using loose equality instead of strict.

Not typing the parameter as string.

Returning the wrong variable.

The function parameter is typed as string. The condition checks if $text !== '' (not empty). Then it returns the uppercase of $text.