using System;

public class Program

{

    static int[] loops;//what's going on with it? xd

    static int numberOfIterations;

    static int numberOfLoops;

    public static void Main()

    {

        Console.WriteLine(Program.InefficientFib(4));

        Console.WriteLine(Program.RecursiveFactorial(4));

        Console.WriteLine(Program.IterativeFactorial(4));

        numberOfLoops = 3;

        numberOfIterations = 2;

        loops = new int[numberOfLoops];

        Program.NestedLoopsRecursive(0);

        //RecursiveFibonacci.Main();

        Console.WriteLine(Program.IterativeFibonacci(5));

    }

    //0.1

    //inefficient fibonacci

    public static long InefficientFib(int n)

    {

        if(n<=2)

        {

            return 1;

        }

        else

        {

            return InefficientFib(n-1)+InefficientFib(n-2);

        }

    }

    //0.2

    public static long RecursiveFactorial(int n)

    {

        if(n<1)

        {

            return 1;

        }

        else

        {

            return n*RecursiveFactorial(n-1);

        }

    }

    //0.3

    public static long IterativeFactorial(int n)

    {

        long result = 1;

        for(int i = n; i>0;i--)

        {

            result *= i;

        }

        return result;

    }

    //0.4 simulation of N nested loops

    public static void NestedLoopsRecursive(int currentLoop)

    {

        if(currentLoop == numberOfLoops)

        {

            PrintLoops();

            return;

        }

        for(int counter = 1; counter <= numberOfIterations; counter++)

        {

            loops[currentLoop] = counter;

            NestedLoopsRecursive(currentLoop + 1);

        }

    }

    public static void PrintLoops()

    {

        for(int i = 0; i<numberOfLoops; i++)

        {

            Console.Write("{0} ", loops[i]);

        }

        Console.WriteLine("----------");

    }

    public static long IterativeFibonacci(int n)

    {

        long fn = 0;

        long fnMinus1 = 1;

        long fnMinus2 = 1;

        for(int i=2;i<n;i++)

        {

            fn = fnMinus1 + fnMinus2;

            fnMinus2 = fnMinus1;

            fnMinus1 = fn;

        }

        return  fn;

    }

}

​

public class RecursiveFibonacci

{

    static long[] numbers;

    public static void Main()

    {

        Console.WriteLine("n: ");

        int n = int.Parse(Console.ReadLine());

        numbers = new long[n+2];

        numbers[1] = 1;

        numbers[2] = 1;

        long result = Fib(n);

        Console.WriteLine(n+"---"+result);

        foreach(long x in numbers)

        {

            Console.Write("{0} ", x);

        }

        Console.WriteLine();

    }

    public static long Fib(int n)

    {

        if(numbers[n] == 0)

        {

            numbers[n] = Fib(n-1)+Fib(n-2);

        }

        //Console.WriteLine(numbers[n]);

        return numbers[n];

    }

}

​

​

​