Control Flow

Control flow statements determine the order in which code executes. C# provides traditional branching and looping constructs along with modern pattern matching features.

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If / Else

The most basic branching statement:

int score = 85;

if (score >= 90)
{
    Console.WriteLine("Grade: A");
}
else if (score >= 80)
{
    Console.WriteLine("Grade: B");
}
else if (score >= 70)
{
    Console.WriteLine("Grade: C");
}
else
{
    Console.WriteLine("Grade: F");
}

Conditional (Ternary) Operator

string result = score >= 60 ? "Pass" : "Fail";

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Switch Statements

Traditional switch with constant patterns:

string dayType = day switch
{
    DayOfWeek.Saturday or DayOfWeek.Sunday => "Weekend",
    _ => "Weekday"
};

Switch Statement (Classic)

switch (command)
{
    case "start":
        Start();
        break;
    case "stop":
        Stop();
        break;
    case "restart":
        Stop();
        Start();
        break;
    default:
        Console.WriteLine("Unknown command");
        break;
}

Switch Expressions (C# 8+)

A more concise syntax that returns a value:

string description = statusCode switch
{
    200 => "OK",
    301 => "Moved Permanently",
    404 => "Not Found",
    500 => "Internal Server Error",
    _ => $"Unknown status: {statusCode}"
};

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Pattern Matching