enum Basics / case / switch

// Basic enum definition
enum EnumName {
    case caseName1
    case caseName2
    case caseName3, caseName4  // Multiple cases can be defined on one line
}

// CaseIterable: allows you to get all cases as an array
enum EnumName: CaseIterable {
    case caseName1
    case caseName2
}

// Basic enum
enum Direction {
    case north
    case south
    case east
    case west
}

// Usage
var heading = Direction.north
heading = .east  // Type can be omitted when it's already known

// Exhaustive matching with switch
switch heading {
case .north:
    print("Heading north")
case .south:
    print("Heading south")
case .east:
    print("Heading east")
case .west:
    print("Heading west")
}

// Iterate over all cases with CaseIterable
enum Season: CaseIterable {
    case spring, summer, autumn, winter
}

print("Number of seasons: \(Season.allCases.count)")
for season in Season.allCases {
    print(season)
}

// Comparison (== / !=)
let day = Direction.north
if day == .north {
    print("Heading north")
}

Unlike C enumerations, Swift's enum is not just an integer alias. It can have methods and properties, and can conform to protocols.

When you use a switch statement on an enum, the compiler checks that all cases are covered. This means any missed cases when a new case is added are caught at compile time.An enum is a value type (like a struct) and is not passed by reference the way a class is.

For enums with raw values (RawValue), see enum RawValue (Int / String).