Raw values for enums in Swift - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of enum raw value access

What is the output of this Swift code snippet?

Swift

enum Direction: String {
    case north = "N"
    case south = "S"
    case east = "E"
    case west = "W"
}

let dir = Direction.east
print(dir.rawValue)

A Direction.east

B "east"

C "E"

D "East"

💡 Hint

Check the raw value assigned to the case east.

The enum Direction has raw values of type String. The case east is assigned the raw value "E". Accessing dir.rawValue prints "E".

❓ Predict Output

intermediate

Raw value default assignment for Int enums

What will be printed by this Swift code?

Swift

enum Weekday: Int {
    case monday = 1
    case tuesday
    case wednesday
}

print(Weekday.tuesday.rawValue)

A 3

B 1

C tuesday

D 2

💡 Hint

Int raw values auto-increment from the first assigned value.

Since monday is assigned 1, tuesday gets 2 automatically, so printing rawValue of tuesday outputs 2.

❓ Predict Output

advanced

Using rawValue initializer with valid and invalid values

What is the output of this Swift code?

Swift

enum StatusCode: Int {
    case success = 200
    case notFound = 404
    case serverError = 500
}

if let status = StatusCode(rawValue: 404) {
    print("Found: \(status)")
} else {
    print("Not found")
}

if let status = StatusCode(rawValue: 201) {
    print("Found: \(status)")
} else {
    print("Not found")
}

A

Found: notFound
Not found

B

Found: notFound
Found: 201

C

Not found
Not found

D

Found: 404
Not found

💡 Hint

rawValue initializer returns nil if no matching case exists.

StatusCode(rawValue: 404) matches notFound case, so prints Found: notFound. 201 does not match any case, so prints Not found.

❓ Predict Output

advanced

Raw values with mixed types in enum

What error or output does this Swift code produce?

Swift

enum MixedRaw: RawRepresentable {
    case intCase(Int)
    case stringCase(String)

    var rawValue: Any {
        switch self {
        case .intCase(let value): return value
        case .stringCase(let value): return value
        }
    }

    init?(rawValue: Any) {
        if let intValue = rawValue as? Int {
            self = .intCase(intValue)
        } else if let stringValue = rawValue as? String {
            self = .stringCase(stringValue)
        } else {
            return nil
        }
    }
}

let a = MixedRaw(rawValue: 10)
print(a?.rawValue ?? "nil")

A nil

B Compile-time error: enums cannot have associated values and raw values

C 10

D Runtime error

💡 Hint

Swift enums with associated values cannot have raw values.

Swift does not allow enums with associated values to have raw values. This code will not compile.

🧠 Conceptual

expert

Raw value uniqueness enforcement

What happens if you define a Swift enum with duplicate raw values like this?

Swift

enum Color: String {
    case red = "R"
    case green = "G"
    case blue = "R"
}

A Compile-time error due to duplicate raw values

B Compiles successfully, last case overwrites previous raw value

C Runtime error when accessing rawValue

D Compiles but rawValue of blue is nil

💡 Hint

Raw values must be unique in Swift enums.

Swift requires raw values to be unique. Duplicate raw values cause a compile-time error.