Why modern PHP matters - Challenge Your Understanding

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of typed properties in PHP 7.4+

What is the output of this PHP code using typed properties introduced in PHP 7.4?

PHP

<?php
class User {
    public int $id;
    public string $name;

    public function __construct(int $id, string $name) {
        $this->id = $id;
        $this->name = $name;
    }
}
$user = new User(1, "Alice");
echo $user->id . ' - ' . $user->name;

A 1 - Alice

B Error: Typed property must be initialized

C 1-Alice

D 1, Alice

💡 Hint

Typed properties require initialization before use.

Typed properties in PHP 7.4 allow declaring variable types in classes. Here, both properties are initialized in the constructor, so accessing them prints their values.

🧠 Conceptual

intermediate

Why use PHP 8's union types?

Which of the following best explains the benefit of union types introduced in PHP 8?

A They allow a variable to accept multiple specified types, improving code clarity and error checking.

B They automatically convert all types to strings for easier output.

C They remove the need for any type declarations in functions.

D They force all variables to be of a single type only.

💡 Hint

Think about how specifying multiple types helps programmers.

Union types let you declare that a variable or parameter can be one of several types, making code more flexible and safer by catching type errors early.

🔧 Debug

advanced

Identify the error with nullsafe operator

What error does this PHP 8 code produce?

PHP

<?php
class Profile {
    public ?string $email = null;
}
$user = null;
echo $user?->profile?->email;

A Notice: Undefined variable 'user'

B Fatal error: Trying to get property of non-object

C Parse error: syntax error near '?->'

D No output, prints nothing

💡 Hint

The nullsafe operator returns null if the variable is null.

The nullsafe operator (?->) safely accesses properties or methods on objects that might be null. Here, $user is null, so the expression returns null and prints nothing.

📝 Syntax

advanced

Correct syntax for match expression

Which option shows the correct syntax for PHP 8's match expression?

PHP

switch ($status) {
    case 1:
        $result = 'One';
        break;
    case 2:
        $result = 'Two';
        break;
    default:
        $result = 'Other';
}

A

$result = match($status) {
    1 => 'One';
    2 => 'Two';
    default => 'Other';
};

B

$result = match($status) {
    1: 'One',
    2: 'Two',
    default: 'Other'
};

C

$result = match($status) {
    1 => 'One',
    2 => 'Two',
    default => 'Other',
};

D

$result = match $status {
    1 => 'One',
    2 => 'Two',
    default => 'Other'
};

💡 Hint

Look for the arrow syntax and commas between cases.

The match expression uses => arrows and commas to separate cases. Parentheses around the variable are required. Semicolons inside the match block cause syntax errors.

🚀 Application

expert

How does PHP 8's JIT improve performance?

Which statement best describes how PHP 8's Just-In-Time (JIT) compiler improves PHP performance?

A JIT caches PHP source files to reduce disk reads.

B JIT compiles PHP code into machine code at runtime, speeding up CPU-intensive tasks.

C JIT converts PHP code into JavaScript for faster browser execution.

D JIT removes all type checks to make code run faster.

💡 Hint

Think about how turning code into machine instructions helps speed.

JIT compiles PHP bytecode into native machine code during execution, which can greatly speed up heavy computations compared to interpreting code line-by-line.