Enums in PHP - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of backed enum value access

What is the output of this PHP code using backed enums?

PHP

<?php
enum Status: string {
    case Pending = 'pending';
    case Completed = 'completed';
}

echo Status::Completed->value;

A pending

B Completed

C Status::Completed

D completed

💡 Hint

Access the string value of the enum case using ->value.

Backed enums in PHP allow each case to have a scalar value. Accessing ->value returns that scalar, here 'completed'.

❓ Predict Output

intermediate

Output of enum method call

What does this PHP code print when calling a method inside an enum?

PHP

<?php
enum Direction {
    case North;
    case South;
    case East;
    case West;

    public function opposite(): Direction {
        return match($this) {
            Direction::North => Direction::South,
            Direction::South => Direction::North,
            Direction::East => Direction::West,
            Direction::West => Direction::East,
        };
    }
}

echo Direction::East->opposite()->name;

A East

B West

C North

D South

💡 Hint

The opposite of East is West according to the match expression.

The method opposite() returns the enum case opposite to the current one. East's opposite is West, so it prints 'West'.

🔧 Debug

advanced

Identify the error in enum declaration

What error does this PHP code raise when declaring this enum?

PHP

<?php
enum Color {
    case Red = 1;
    case Green = 'green';
    case Blue = 3;
}

A Fatal error: Backed enum cases must have the same scalar type

B No error, code runs fine

C TypeError: Enum case values must be integers

D Syntax error: Missing semicolon after case

💡 Hint

Backed enums require all cases to have the same scalar type.

Backed enums must have all cases with the same scalar type (all int or all string). Mixing int and string causes a fatal error.

📝 Syntax

advanced

Which option causes a syntax error?

Which of these enum declarations will cause a syntax error in PHP?

A enum Status: string { case Active = 'yes'; case Inactive = 'no'; }

B enum Status { case Active; case Inactive; }

C enum Status { case Active; case Inactive }

D enum Status: int { case Active = 1; case Inactive = 0; }

💡 Hint

Check for missing semicolons after case declarations.

Option C misses a semicolon after 'case Inactive', causing a syntax error.

🚀 Application

expert

Number of cases in a backed enum

Given this backed enum, how many cases does it contain?

PHP

<?php
enum HttpStatus: int {
    case OK = 200;
    case Created = 201;
    case Accepted = 202;
    case NoContent = 204;
}

$cases = HttpStatus::cases();
echo count($cases);

A 4

B 0

C 5

D 3

💡 Hint

Count the number of case declarations inside the enum.

The enum defines 4 cases: OK, Created, Accepted, NoContent. The count of cases() returns 4.