Round #744

Use a switch expression to map an enum value to a string.

### Enum to String Mapping using Switch Expression Here's an example of how you can use a switch expression to map an enum value to a string in C#. ```csharp // Define an enum public enum Color { Red, Green, Blue } public class Program { public static void Main() { // Use a switch expression to map an enum value to a string Color color = Color.Green; string colorName = color switch { Color.Red => "Red", Color.Green => "Green", Color.Blue => "Blue", _ => "Unknown color" }; Console.WriteLine(colorName); // Outputs: Green } } ``` In this example, the switch expression checks the value of the `color` variable and returns the corresponding string. If the value doesn't match any of the specified cases, it returns "Unknown color". ### Using a Dictionary for Mapping Alternatively, you can use a dictionary to map enum values to strings. This approach can be more efficient and easier to maintain if you have a large number of enum values. ```csharp // Define an enum public enum Color { Red, Green, Blue } public class Program { private static readonly Dictionary<Color, string> colorMap = new() { { Color.Red, "Red" }, { Color.Green, "Green" }, { Color.Blue, "Blue" } }; public static void Main() { // Use the dictionary to map an enum value to a string Color color = Color.Green; string colorName = colorMap.TryGetValue(color, out string? name) ? name : "Unknown color"; Console.WriteLine(colorName); // Outputs: Green } } ``` In this example, the `colorMap` dictionary stores the mapping between enum values and strings. The `TryGetValue` method is used to retrieve the string value for a given enum value, and if the value is not found, it returns "Unknown color".

```csharp using System; public enum Color { Red, Green, Blue } public class Program { public static string GetColorName(Color color) => color switch { Color.Red => "Red", Color.Green => "Green", Color.Blue => "Blue", _ => throw new ArgumentOutOfRangeException(nameof(color), color, null) }; public static void Main() { Console.WriteLine(GetColorName(Color.Red)); // Outputs: Red Console.WriteLine(GetColorName(Color.Green)); // Outputs: Green Console.WriteLine(GetColorName(Color.Blue)); // Outputs: Blue } } ``` This C# code uses a switch expression to map an enum value of type `Color` to its corresponding string representation. The `GetColorName` method takes a `Color` enum value as input and returns the associated string. If the input enum value does not match any of the specified cases, it throws an `ArgumentOutOfRangeException`. The switch expression is a concise way to express simple conditional logic, making the code more readable and efficient. The `_` wildcard pattern is used to handle any unexpected enum values, ensuring that the method is robust and handles potential errors.