switch Statement & Expression

Syntax

switch (value) {\n  case option:\n    // code\n    break;\n  default:\n    // code\n}

Examples

int day = 3;
string dayName;

switch (day)
{
    case 1:
        dayName = "Monday";
        break;
    case 2:
        dayName = "Tuesday";
        break;
    case 3:
        dayName = "Wednesday";
        break;
    default:
        dayName = "Unknown";
        break;
}

Console.WriteLine(dayName);  // Wednesday

int month = 4;
string season;

switch (month)
{
    case 12:
    case 1:
    case 2:
        season = "Winter";
        break;
    case 3:
    case 4:
    case 5:
        season = "Spring";
        break;
    default:
        season = "Other";
        break;
}

Console.WriteLine(season);  // Spring

int day = 6;

string dayType = day switch
{
    1 or 2 or 3 or 4 or 5 => "Weekday",
    6 or 7 => "Weekend",
    _ => "Invalid day"
};

Console.WriteLine(dayType);  // Weekend

object item = 42;

string description = item switch
{
    int n when n > 0 => $"Positive number: {n}",
    int n when n < 0 => $"Negative number: {n}",
    int => "Zero",
    string s => $"A string: {s}",
    null => "Nothing here",
    _ => "Unknown type"
};

Console.WriteLine(description);  // Positive number: 42

Best practices

• Never forget break in a traditional switch statement - a missing break causes execution to fall through into the next case
• Prefer the modern switch expression (C# 8+) when your target version supports it - it removes the fall-through pitfall and is more concise
• Always include a default case (or _ in a switch expression) to handle unexpected values gracefully
• Use switch over a long else if chain when comparing one variable against several specific, discrete values or patterns

At a glance

Purpose

Applications on the .NET platform

File extension

.cs

Runs in

.NET runtime

Usually used with

.NET SDK and libraries

Specifications & further reading

• C# language reference

Related C# documentation