using System;

public class Program

{

    public static void Main()

    {

        int someVal = 2;

        int MyLocalMethod(int a, int b) {

            return a + b - someVal;

        }

        Func<int, int, int> myLambda = (a, b) => a + b;

        Func<int, int, int> myLambda2 = (a, b) => a * (b + someVal); // Note that lambdas can "capture" values from the enclosing scope.

        Console.WriteLine($"myLambda: {myLambda(2, 3)}");

        Console.WriteLine($"myLambda: {myLambda2(2, 3)}");

        Console.WriteLine($"MyMethod: {Program.MyMethod(2, 3)}");

        Console.WriteLine($"MyMethod2: {MyLocalMethod(2, 3)}");

        int[] array = {1, 2, 3, 4, 5};

        Console.WriteLine($"DoShit myLambda: {DoShit(array, 0, myLambda)}");

        Console.WriteLine($"DoShit myLambda2: {DoShit(array, 1, myLambda2)}");

        Console.WriteLine($"DoShit MyMethod: {DoShit(array, 2, Program.MyMethod)}");

        Console.WriteLine($"DoShit MyLocalMethod: {DoShit(array, 2, MyLocalMethod)}");

    }

    public static int MyMethod(int a, int b)

    {

        return a - b;

    }

    public static int DoShit(int[] vals, int start, Func<int, int, int> f) {

        int n = start;

        foreach( int val in vals ) {

            n = f(n, val);

        }

        return n;

    }

}