Enum declaration and cases in Swift

Introduction

Enums help you group related values under one name. They make your code easier to read and use.

When you want to list fixed options like days of the week.

When you need to handle different states like loading, success, or error.

When you want to organize related values clearly instead of using many constants.

Syntax

Swift

enum EnumName {
    case case1
    case case2
    case case3
}

Each case represents a possible value of the enum.

You can use multiple cases on one line separated by commas, like: case case1, case2, case3

Examples

This enum lists four directions as possible values.

Swift

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

Here, multiple cases are declared on one line for traffic light colors.

Swift

enum Light {
    case red, yellow, green
}

This enum represents weekdays from Monday to Friday.

Swift

enum Weekday {
    case monday
    case tuesday
    case wednesday
    case thursday
    case friday
}

Sample Program

This program defines a Weather enum with four cases. It sets today's weather to sunny and uses a switch to print a message based on the weather.

Swift

enum Weather {
    case sunny
    case rainy
    case cloudy
    case windy
}

var todayWeather = Weather.sunny

switch todayWeather {
case .sunny:
    print("It's a bright and sunny day!")
case .rainy:
    print("Don't forget your umbrella.")
case .cloudy:
    print("It might rain later.")
case .windy:
    print("Hold onto your hat!")
}

Important Notes

You can use enums to make your code safer by limiting values to known options.

Use a dot (.) before case names when the enum type is already known, like .sunny.

Summary

Enums group related values under one name.

Each case is a possible value of the enum.

Use enums to write clearer and safer code.