C# Basics — Methods

8 min read · Emre Ulutabak

What is a method?

You woke up in the morning, brushed your teeth. Did it again at noon. And in the evening. You repeated the same action every time — but you only learned it once.

Code works the same way. Instead of writing the same thing over and over, you write it once, give it a name, and call it whenever needed. This is called a method.

csharp

static void Selamla()
{
    Console.WriteLine("Merhaba!");
}

Selamla();
Selamla();
Selamla();

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You wrote the method once, called it three times. If you want to change it, you only change one place.

Why use methods?

Code written without methods quickly becomes unreadable. Imagine copying the same block to 10 places — if you find a bug in one, you have to fix all 10.

Methods make code readable, maintainable, and reusable. These three properties are the foundation of good software.

Void vs Return

Some methods do something but don't return a value — these are void. Others produce something and give it back.

Think of a cook in the kitchen: a void cook makes the food but doesn't hand it to you. A return cook cooks it and hands you the plate.

csharp

static void Yazdir(string mesaj)
{
    Console.WriteLine(mesaj);
}

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

Yazdir("Merhaba");
int sonuc = Topla(3, 5);
Console.WriteLine(sonuc);

Parameters

You can pass information into methods from outside — these are called parameters. Think of a calculator: it doesn't just add, you also need to tell it which numbers to add.

csharp

static void Karşıla(string isim)
{
    Console.WriteLine($"Merhaba, {isim}!");
}

Karşıla("Emre");
Karşıla("Ayşe");
Karşıla("Mehmet");

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As the number of parameters increases, the method gets complex. If there are more than 3 parameters, reconsider the design.

Golden rules

There are some fundamental rules learned over years. Knowing these separates you from mid-level developers:

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A method should do only one thing. If it does more than one thing, split it.

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Method names should be verbs: Calculate(), Save(), Get() — what it does should be clear from the name.

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A method exceeding 20 lines is likely doing more than one thing. Review it.

MINI QUIZ

Which of the following is correct?

void methods always return a value

Every method must contain return

void methods don't return a value, they just do work

return is only used for strings