Loops

using System;
using System.Numerics;

class LoopsDemos
{
    static void Main()
    {
        /*
        //int n = int.Parse(Console.ReadLine());
        //int i = 0; // initialization
        //while (i < n) // condition
        //{
        //    Console.WriteLine(i);
        //    i++; // update
        //}
        */
        /*
        int n = int.Parse(Console.ReadLine());
        int i = 0; // initialization
        int sum = 0;
        while (i <= n) // condition
        {
            sum += i;
            i++; // update
        }
        Console.WriteLine(sum);
        */
        /*
        int n = int.Parse(Console.ReadLine());
        // int i = 0; // initialization
        // int sum = 0;
        BigInteger sum = 0;
        while (n > 0) // condition
        {
            checked
            {
                sum += n;
            }
            n--; // update
        }
        Console.WriteLine(sum);
        */
        /*
        int n = int.Parse(Console.ReadLine());
        int i = 2;
        bool isprime = true;
        while (i < n)
        {
            if (n % i == 0)
            {
                isprime = false;
                break;
            }

            i++;
        }
        Console.WriteLine("the number {0} is prime: {1}", n, isprime);
        */
        /*
        int n = int.Parse(Console.ReadLine());
        int i = 2;
        int maxDivider = (int)Math.Sqrt(n);
        bool isPrime = true;
        while (i <= maxDivider)
        {
            if (n % i == 0)
            {
                isPrime = false;
                break;
            }

            i++;
        }
        Console.WriteLine("The number {0} is prime: {1}", n, isPrime);
        */
        /*
        int n = int.Parse(Console.ReadLine());
        int i = 2;
        int maxDivider = (int)Math.Sqrt(n);
        bool isPrime = true;
        while (isPrime && i <= maxDivider)
        {
            if (n % i == 0)
            {
                isPrime = false;
                // break;
            }

            i++;
        }
        Console.WriteLine("The number {0} is prime: {1}", n, isPrime);
        */

        /*
        Random rand = new Random();
        int n = rand.Next(1, 10);
        int i = 0;
        while (i < n)
        {
            Console.WriteLine("i = {0} n = {1}", i, n);
            i++;
        }
        */

        /*
        // factorial 0!= 1 n! = (n-1)!*n;
        int n = int.Parse(Console.ReadLine());
        int factorial = 1;
        while (n > 0)
        {
            checked
            {
                factorial *= n--;
            }

        }
        Console.WriteLine(factorial);
        */
        /*
        int n = int.Parse(Console.ReadLine());
        BigInteger factorial = 1;
        while (n > 0)
        {
            checked
            {
                factorial *= n--;
            }

        }
        Console.WriteLine(factorial);
        */
        /* This is not working factorial 0
        int n = int.Parse(Console.ReadLine());
        BigInteger factorial = 1;
        do
        {
            checked
            {
                factorial *= n--;
            }

        } while (n > 0);

        Console.WriteLine(factorial);
        */
        /*
        string numberAsString = Console.ReadLine();
        int n = Convert.ToInt32(numberAsString);
        int factorial = 1;
        if (n != 0)
        {
            do
            {
                factorial *= n;
                n--;
            } while (n > 0);

        }
        Console.WriteLine("n! = " + factorial);
        */
        /*
        ConsoleKeyInfo cki;
        cki = Console.ReadKey();
        Console.WriteLine(cki.Key == ConsoleKey.RightArrow);
        int positionX = 0;
        int positionY = 0;

        do {
            while (!Console.KeyAvailable)
            {
                // Console.WriteLine("Cycle trough your live");
                Console.Clear();
                Console.SetCursorPosition(positionX, positionY);
                Console.Write("*");
                System.Threading.Thread.Sleep(100);
            }
            cki = Console.ReadKey(true);
            switch (cki.Key)
            {
                case ConsoleKey.RightArrow:
                    positionX++;
                    break;
                case ConsoleKey.LeftArrow:
                    positionX--;
                    break;
                case ConsoleKey.DownArrow:
                    positionY++;
                    break;
                case ConsoleKey.UpArrow:
                    positionY--;
                    break;
            }

        } while (cki.Key != ConsoleKey.Escape);
        */
        /*
        int n = 0;

        do
        {
            Console.Write("Please enter a positive number: ");
            n = int.Parse(Console.ReadLine());
        } while(n < 0);
        */
        /*
        int n = int.Parse(Console.ReadLine());
        int m = int.Parse(Console.ReadLine());
        int number = n;
        decimal product = 1;
        do
        {
            product *= number;
            number++;
        }
        while (number <= m);
        Console.WriteLine("product[{0}..{1}] = {2}", n, m, product);
        */
        /*
        int i = 0;
        while (i < 10)
        {
            Console.WriteLine(i);
            i++;
        }
        */
        /*
        for (int i = 0; i < 10; i++)
        {
            Console.WriteLine(i);
        }
        */
        /*
        int sum = 0;
        for (int i = 0; i <= 5; i++)
        {
            sum += i;
        }
        Console.WriteLine(sum);
        */
        /*
        int factorial = 1;
        for (int i = 1; i <= 5; i++)
        {
            factorial *= i;
        }
        Console.WriteLine(factorial);
        */
        /*
        Random rand = new Random();
        int n = rand.Next(1, 10);

        for (;;)
        {
            Console.WriteLine("cycle");
        }
        */
        /*
        for (int i = 1, sum = 1; i <= 128; i = i * 2, sum += i)
        {
            Console.WriteLine("i={0}, sum={1}", i, sum);
        }
        */

        /*
        int n = int.Parse(Console.ReadLine());
        int m = int.Parse(Console.ReadLine());
        decimal result = 1;
        for (int i = 0; i < m; i++)
        {
            result *= n;
        }
        Console.WriteLine("n^m = " + result);
        */
        /*
        int n = int.Parse(Console.ReadLine());
        int sum = 0;
        for (int i = 1; i <= n; i += 2)
        {
            if (i % 7 == 0)
            {
                continue;
            }
            sum += i;
        }
        Console.WriteLine("sum = {0}", sum);
        */
        /*
        string[] group = { "Stoyan", "Vasko", "Petko", "Ivan" };

        // foreach (string name in group)
        foreach (var name in group)
        {
            Console.WriteLine(name);
        }
        */
        /*
        string[] days = {
   "Monday", "Tuesday", "Wednesday", "Thursday",
   "Friday", "Saturday", "Sunday" };
        foreach (var day in days)
        {
            Console.WriteLine(day);
        }
        */
        /*
        int n = int.Parse(Console.ReadLine());

        for (int i = 0; i < n; i++)
        {
            for (int j = 0; j < i; j++)
            {
                Console.Write(j);
            }
            Console.WriteLine();
        }
        */
        /*
        int n = int.Parse(Console.ReadLine());
        int m = int.Parse(Console.ReadLine());
        for (int number = n; number <= m; number++)
        {
            bool prime = true;
            int divider = 2;
            int maxDivider = (int)Math.Sqrt(number);
            while (divider <= maxDivider)
            {
                if (number % divider == 0)
                {
                    prime = false;
                    break;
                }
                divider++;
            }
            if (prime)
                Console.Write("{0} ", number);
        }
        */
        /*
        int sum = 0;
        int i = 0;
        while(i < 100)
        {
            Console.WriteLine(i);
            if (i % 2 == 0)
            {
                i++;
                continue;
            }

            sum += i;
            i++;
        }
        */
        /*
        breakIn:;

        int outerCounter = 0;
        for (int outer = 0; outer < 10; outer++)
        {
            for (int inner = 0; inner < 10; inner++)
            {
                if (inner % 3 == 0)
                    continue; if (outer == 7)
                    break; if (inner + outer > 9)
                    goto breakOut;
            }
            outerCounter++;
        }
        breakOut:
        goto breakIn;
        */
        /*
        for (int a = 1; a <= 9; a++)
            for (int b = 0; b <= 9; b++)
                for (int c = 0; c <= 9; c++)
                    for (int d = 0; d <= 9; d++)
                        if (a + b == c + d)
                            Console.WriteLine("{0}{1}{2}{3}", a, b, c, d);
        */
        /*
        int counter = 0;
        int i1, i2, i3, i4, i5, i6;
        for (i1 = 1; i1 <= 44; i1++)
            for (i2 = i1 + 1; i2 <= 45; i2++)
                for (i3 = i2 + 1; i3 <= 46; i3++)
                    for (i4 = i3 + 1; i4 <= 47; i4++)
                        for (i5 = i4 + 1; i5 <= 48; i5++)
                            for (i6 = i5 + 1; i6 <= 49; i6++)
                            {
                                // Console.WriteLine("{0} {1} {2} {3} {4} {5}", i1, i2, i3, i4, i5, i6);
                                // Try to comment the above row to speed up the program
                                counter++;
                            }
        Console.WriteLine("{0} combinations", counter);
        */
        // Console.ForegroundColor

    }

    static int factorial(int n)
    {
        int factorial = 1;
        while (n > 0)
        {
            checked
            {
                factorial *= n--;
            }

        }
        return factorial;
    }
}