Methods, ref/out/in Modifiers, Delegates & Action/Func Lambdas

1Concept

C# supports pass-by-reference modifiers: ref (pass by ref, read-write), out (callee must assign before return), and in (read-only reference avoiding copy of large structs). Action and Func delegates enable functional programming.

2Architecture Diagram

ref  T : Pass address, variable must be initialized by caller
out  T : Pass address, variable MUST be initialized by callee
in   T : Pass address, read-only (zero copy overhead)

3Code Example

using System;

class Program
{
    static bool TryParseInteger(string input, out int result)
    {
        return int.TryParse(input, out result);
    }

    static void Main()
    {
        // Out parameter
        if (TryParseInteger("4500", out int parsedVal))
        {
            Console.WriteLine($"Successfully parsed integer: {parsedVal}");
        }

        // Func & Action Lambdas
        Func<int, int, int> multiply = (a, b) => a * b;
        Action<string> logMessage = msg => Console.WriteLine($"[LOG] {msg}");

        logMessage($"Result: {multiply(8, 9)}");
    }
}

4Expected Output

Successfully parsed integer: 4500
[LOG] Result: 72

5Key Takeaways

• ✓Use out parameters for TryParse patterns returning status boolean and value.
• ✓Use in modifiers for large readonly structs (in Vector3D) to avoid copy overhead.
• ✓Func<T1, T2, TResult> has a return value; Action<T> returns void.