Enum methods and computed properties in Swift - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a computed property that returns a description for the enum case.

Swift

enum Direction {
    case north, south, east, west
    var description: String {
        switch self {
        case .north: return "Going [1]"
        case .south: return "Going south"
        case .east: return "Going east"
        case .west: return "Going west"
        }
    }
}

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

Aleft

Bup

Cnorth

Dright

Attempts:

3 left

💡 Hint

Common Mistakes

Using a direction word that doesn't match the case name.

Leaving the placeholder blank.

The computed property returns a string describing the enum case. For the .north case, it should return "Going north".

2fill in blank

medium

Complete the method to return true if the direction is vertical (north or south).

Swift

enum Direction {
    case north, south, east, west
    func isVertical() -> Bool {
        return self == .[1] || self == .south
    }
}

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

Aup

Beast

Cwest

Dnorth

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'east' or 'west' which are horizontal directions.

Using a non-existent case like 'up'.

The method checks if the direction is vertical by comparing to .north or .south. The blank must be 'north'.

3fill in blank

hard

Fix the error in the method that returns the opposite direction.

Swift

enum Direction {
    case north, south, east, west
    func opposite() -> Direction {
        switch self {
        case .north: return .[1]
        case .south: return .north
        case .east: return .west
        case .west: return .east
        }
    }
}

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

Asouth

Bnorth

Ceast

Dwest

Attempts:

3 left

💡 Hint

Common Mistakes

Returning .north for the .north case causing no change.

Returning east or west which are not opposites of north.

The opposite of north is south, so the method should return .south for the .north case.

4fill in blank

hard

Fill both blanks to create a computed property that returns true if the direction is horizontal.

Swift

enum Direction {
    case north, south, east, west
    var isHorizontal: Bool {
        return self == .[1] || self == .[2]
    }
}

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

Aeast

Bnorth

Cwest

Dsouth

Attempts:

3 left

💡 Hint

Common Mistakes

Using north or south which are vertical directions.

Swapping the order of east and west is acceptable but must match correct_answer.

Horizontal directions are east and west, so the computed property returns true if self is .east or .west.

5fill in blank

hard

Fill all three blanks to create a method that returns a string with the direction and its opposite.

Swift

enum Direction {
    case north, south, east, west
    func descriptionWithOpposite() -> String {
        let opposite: Direction
        switch self {
        case .north: opposite = .[1]
        case .south: opposite = .north
        case .east: opposite = .west
        case .west: opposite = .east
        }
        return "\([2]\) is opposite to \([3]\)"
    }
}

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

Asouth

Bself

Copposite

Dnorth

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong opposite direction for .north.

Using literal strings instead of variables in the return statement.

The method assigns opposite for .north as .south, then returns a string using 'self' and 'opposite' to describe the relation.