C# Switch Statements

Switch statements in C# provide an efficient way to handle multiple conditions based on a single expression. They offer a cleaner alternative to long chains of if-else statements, especially when dealing with discrete values.

Basic Syntax

The basic structure of a switch statement in C# is as follows:

switch (expression)
{
    case value1:
        // Code to execute if expression equals value1
        break;
    case value2:
        // Code to execute if expression equals value2
        break;
    default:
        // Code to execute if no case matches
        break;
}
    

The expression is evaluated once, and its value is compared against each case. When a match is found, the corresponding code block is executed.

Key Features

• The break statement is required at the end of each case to prevent fall-through.
• The default case is optional but recommended for handling unexpected values.
• Multiple cases can be combined if they share the same code block.

Example: Days of the Week

Here's a practical example using a switch statement to handle days of the week:

string day = "Monday";
string message;

switch (day)
{
    case "Monday":
    case "Tuesday":
    case "Wednesday":
    case "Thursday":
    case "Friday":
        message = "It's a weekday.";
        break;
    case "Saturday":
    case "Sunday":
        message = "It's the weekend!";
        break;
    default:
        message = "Invalid day.";
        break;
}

Console.WriteLine(message);
    

This example demonstrates how multiple cases can share the same code block, reducing repetition.

Pattern Matching in Switch Statements

C# 7.0 introduced pattern matching in switch statements, allowing for more complex conditions:

object obj = 42;

switch (obj)
{
    case int i when i > 0:
        Console.WriteLine("Positive integer");
        break;
    case int i:
        Console.WriteLine("Non-positive integer");
        break;
    case string s:
        Console.WriteLine($"String: {s}");
        break;
    default:
        Console.WriteLine("Unknown type");
        break;
}
    

This advanced feature enables type checking and conditional matching within the switch statement.

Best Practices

• Use switch statements when you have multiple conditions based on a single variable.
• Ensure all possible cases are handled, including a default case.
• Keep case blocks short and focused. Consider extracting complex logic into separate methods.
• Use C# If-Else Statements for more complex conditional logic that doesn't fit well in a switch structure.

Conclusion

Switch statements in C# offer a clean and efficient way to handle multiple conditions. They improve code readability and maintainability, especially when dealing with discrete values. As you continue your C# journey, you'll find switch statements to be a valuable tool in your programming toolkit.

For more control flow structures, explore C# While Loops and C# For Loops.