Methods and Parameters

C# in Visual Studio 2026 — a hands-on guide for developers at every level.

Defining a Method

static int Add(int a, int b)
{
    return a + b;
}

Console.WriteLine(Add(3, 7));  // 10

Expression-Bodied Methods

For single-expression methods, you can use the arrow syntax:

static int Square(int n) => n * n;
static string Greet(string name) => $"Hello, {name}!";

Default and Named Parameters

static void PrintInfo(string name, int age = 0, string city = "Unknown")
    => Console.WriteLine($"{name}, {age}, {city}");

PrintInfo("Alice");                      // Alice, 0, Unknown
PrintInfo("Bob", 25);                   // Bob, 25, Unknown
PrintInfo("Carol", city: "Paris");     // Carol, 0, Paris

ref and out Parameters

static void Swap(ref int x, ref int y)
{
    int temp = x; x = y; y = temp;
}

int a = 5, b = 10;
Swap(ref a, ref b);
Console.WriteLine($"{a}, {b}");  // 10, 5

params Array

static int Sum(params int[] numbers)
    => numbers.Sum();  // using LINQ

Console.WriteLine(Sum(1, 2, 3));         // 6
Console.WriteLine(Sum(10, 20, 30, 40)); // 100