Why traits are needed in PHP - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to use a trait in a class.

PHP

<?php
trait Logger {
    public function log($msg) {
        echo $msg;
    }
}

class User {
    use [1];
}

$user = new User();
$user->log('Hello');
?>

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

ATraitLogger

BLog

CLogger

DLogging

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong trait name that does not exist.

Forgetting to use the use keyword inside the class.

The use keyword includes the trait named Logger inside the class.

2fill in blank

medium

Complete the code to fix the error when two traits have the same method name.

PHP

<?php
trait A {
    public function hello() {
        echo 'Hello from A';
    }
}

trait B {
    public function hello() {
        echo 'Hello from B';
    }
}

class MyClass {
    use A, B {
        [1]::hello insteadof [2];
    }
}

$obj = new MyClass();
$obj->hello();
?>

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

AA

BB

CMyClass

Dhello

Attempts:

3 left

💡 Hint

Common Mistakes

Not resolving method name conflicts causes fatal errors.

Swapping the order of traits in the conflict resolution.

When two traits have the same method, you must specify which one to use with insteadof. Here, A::hello insteadof B means use hello from trait A.

3fill in blank

hard

Fix the error in the code by completing the blank to call the trait method inside the class method.

PHP

<?php
trait HelloWorld {
    public function sayHello() {
        echo 'Hello World';
    }
}

class MyClass {
    use HelloWorld;

    public function sayHello() {
        [1]::sayHello();
        echo ' from MyClass';
    }
}

$obj = new MyClass();
$obj->sayHello();
?>

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

AHelloWorld

Bself

Cparent

D$this

Attempts:

3 left

💡 Hint

Common Mistakes

Using parent or self instead of the trait name.

Trying to call the method on $this which causes recursion.

To call the trait method inside the class method, use the trait name followed by :: and the method name.

4fill in blank

hard

Fill both blanks to create a trait with a method and use it in a class.

PHP

<?php
trait [1] {
    public function greet() {
        echo 'Hi!';
    }
}

class Person {
    use [2];
}

$p = new Person();
$p->greet();
?>

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

AGreeter

BPerson

CGreeterTrait

DGreet

Attempts:

3 left

💡 Hint

Common Mistakes

Using different names for the trait declaration and usage.

Confusing class names with trait names.

The trait name must be the same where it is declared and used. Here, Greeter is used in both places.

5fill in blank

hard

Fill all three blanks to define a trait, use it in a class, and call its method.

PHP

<?php
trait [1] {
    public function sayHi() {
        echo 'Hi there!';
    }
}

class [2] {
    use [3];
}

$obj = new [2]();
$obj->sayHi();
?>

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

AFriendly

BGreeter

DUser

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up trait and class names.

Using different trait names in declaration and usage.

The trait is named Friendly, the class is User, and the class uses the trait Friendly.