using System;

public class Program

{

    public static void Main()

    {

    // 1. Create a console application that uses a (1) while and (2) a for loop to calculate the product of the first 10 and 20 integer numbers.

        // Start at 1.

        // You will write 2 while and 2 for loop statements.

        // for loop statements

        int i;

        long product = 1;

        for (i = 1; i <= 10; i++) 

        {

            product *= i;

        }

        Console.WriteLine("The product of the first 10 integers is {0}.", product);

        product = 1;

        for (i = 1; i <= 20; i++) 

        {

            product *= i;

        }

        Console.WriteLine("The product of the first 20 integers is {0}.", product);

        Console.WriteLine();

        // while loop statements

        product = 1;

        i = 1;

        while (i <= 10) 

        {

            product *= i;

            i++;

        }

        Console.WriteLine("The product of the first 10 integers is {0}.", product);

        product = 1;

        i = 1;

        while (i <= 20) 

        {

            product *= i;

            i++;

        }

        Console.WriteLine("The product of the first 20 integers is {0}.", product); 

        Console.WriteLine();

    // 2. For the Gauss in you: Given m=1777 and n=2022, what is the sum of the numbers between m and n (both included in the sum)?

        // Add this for loop to your program above.

        // As a brain teaser (not required to solve), see slide #12 to find inspiration to derive a formula for this problem.

        long sum = 0;

        for (i = 1777; i <= 2022; i++) 

        {

            sum += i;

        }

        Console.WriteLine("Given m = 1777 and n = 2022, the sum of the numbers between m and n is {0}.", sum);

    }

}