Methods & Parameters

🔷 C# Programming Lesson 7 Beginner

Methods are reusable, modular code blocks. C# provides parameter modifiers like ref, out, and params to control how variables are passed.

1 Parameter Modifiers: out, ref, and params

C# parameter modifiers extend standard pass-by-value behaviors:

ref: Passes a variable by reference. The variable must be initialized before it is passed to the method.
out: Used to return multiple values from a method. The variable does not need to be initialized before it is passed, but the method **must assign a value** to it before returning.
params: Allows a method to accept a variable number of arguments of the same type, bundling them into an array dynamically.

2 Parameter Modifiers Code

Let's run a program illustrating methods, overloading, and C# parameter modifiers:

C# — Methods ▶ Run Code

using System;

class Program {
    // 1. ref parameter (modifies the caller's variable)
    static void DoubleValue(ref int x) {
        x *= 2;
    }

    // 2. out parameter (returns output values)
    static void CalculateArea(int radius, out double area) {
        area = Math.PI * radius * radius;
    }

    // 3. params array
    static int SumValues(params int[] numbers) {
        int sum = 0;
        foreach (int n in numbers) sum += n;
        return sum;
    }

    static void Main() {
        int score = 50;
        DoubleValue(ref score);
        Console.WriteLine("After ref double: " + score);

        CalculateArea(5, out double calculatedArea);
        Console.WriteLine("Area via out: " + calculatedArea);

        Console.WriteLine("Sum via params: " + SumValues(1, 2, 3, 4, 5));
    }
}

3 Code Challenge

Challenge: Write a method called `Divide` that takes two integers and uses an `out` parameter to return the remainder of the division. Call the method and print both the quotient and the remainder.