Methods and Parameters

Methods are the building blocks of C# programs. They encapsulate reusable logic, accept input through parameters, and return results. This lesson covers method declarations, parameter passing, overloading, and modern syntax.

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Defining Methods

A method has a return type, a name, and zero or more parameters:

// Method with return value
int Add(int a, int b)
{
    return a + b;
}

// Void method (no return value)
void PrintGreeting(string name)
{
    Console.WriteLine($"Hello, {name}!");
}

Calling Methods

int sum = Add(3, 5);       // 8
PrintGreeting("Alice");    // Hello, Alice!

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Expression-Bodied Methods

For simple one-line methods, use the => syntax:

int Add(int a, int b) => a + b;

string Greet(string name) => $"Hello, {name}!";

void Log(string message) => Console.WriteLine($"[LOG] {message}");

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Parameters

Default Parameters

void SendEmail(string to, string subject = "No Subject", int priority = 1)
{
    Console.WriteLine($"To: {to}, Subject: {subject}, Priority: {priority}");
}

SendEmail("alice@example.com");                          // Uses defaults
SendEmail("bob@example.com", "Meeting", 3);              // All specified
SendEmail("carol@example.com", priority: 5);             // Named argument

Named Arguments

Named arguments let you specify parameters in any order:

SendEmail(
    priority: 2,
    to: "dave@example.com",
    subject: "Urgent"
);

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