public void AddTest()
        {
            // arrange
            Calculator calc = new Calculator();
            int number1 = 5;
            int number2 = 7;

            int expected = 12;

            // act
            int actual = calc.Add(number1, number2);

            // assert
            Assert.AreEqual(expected, actual);
        }
        static void Main(string[] args)
        {
            Console.WriteLine("ADDITION");
            Console.WriteLine("First factor:");
            string stringA = Console.ReadLine();
            int    a       = int.Parse(stringA);

            Console.WriteLine("Second factor:");
            string stringB = Console.ReadLine();
            int    b       = int.Parse(stringB);

            Console.WriteLine("The result is " + Calculator.Add(a, b));
            Console.WriteLine(">>>Press Enter<<<");
            Console.ReadKey();

            Console.WriteLine("");
            Console.WriteLine("SUBTRACTION");
            Console.WriteLine("First factor:");
            string stringC = Console.ReadLine();
            int    c       = int.Parse(stringC);

            Console.WriteLine("Second factor:");
            string stringD = Console.ReadLine();
            int    d       = int.Parse(stringD);

            Console.WriteLine("The result is " + Calculator.Subtract(a, b));
            Console.WriteLine(">>>Press Enter<<<");
            Console.ReadKey();

            Console.WriteLine("");
            Console.WriteLine("SUM MORE NUMBERS");
            Console.WriteLine("How many numbers would you like to sum?");
            string sumnumbers = Console.ReadLine();
            int    count      = 1;

            int[] anarray = new int[int.Parse(sumnumbers)];
            for (int i = 0; i < anarray.Length; i++)
            {
                Console.WriteLine("Factor " + count + ":");
                count++;
                anarray[i] = int.Parse(Console.ReadLine());
            }
            Console.WriteLine("Result:" + Calculator.Sum(anarray));
            Console.WriteLine(">>>Press enter<<<");
            Console.ReadKey();


            Console.WriteLine("");
            Console.WriteLine("MULTIPLY");
            Console.WriteLine("How many numbers would you like to multiply?");
            string multnumbers = Console.ReadLine();
            int    count2      = 1;

            int[] anarray2 = new int[int.Parse(multnumbers)];
            for (int i = 0; i < anarray2.Length; i++)
            {
                Console.WriteLine("Factor " + count2 + ":");
                count2++;
                anarray2[i] = int.Parse(Console.ReadLine());
            }
            Console.WriteLine("Result:" + Calculator.Multiply(anarray2));
            Console.WriteLine(">>>Press enter<<<");
            Console.ReadKey();

            Console.WriteLine("");
            Console.WriteLine("POWER");
            Console.WriteLine("Number:");
            string stringnumber = Console.ReadLine();
            int    yournumber   = int.Parse(stringnumber);

            Console.WriteLine("Exponent:");
            string exponent     = Console.ReadLine();
            int    yourexponent = int.Parse(exponent);

            Console.WriteLine("The result is " + Calculator.Power(yournumber, yourexponent));
            Console.WriteLine(">>>Press Enter<<<");
            Console.ReadKey();

            Console.WriteLine("");
            Console.WriteLine("FACTORIAL");
            Console.WriteLine("Factorial of:");
            string stringfactorial = Console.ReadLine();
            int    yourfactorial   = int.Parse(stringfactorial);

            Console.WriteLine("The result is " + Calculator.Factorial(yourfactorial));
            Console.WriteLine(">>>Press Enter<<<");
            Console.ReadKey();

            Console.WriteLine("");
            Console.WriteLine("Thanks for you cooperation, next time you should use a true calculator.");
            Console.WriteLine(">>>>>Press Enter to cause a nuclear explosion<<<<<");
            Console.ReadKey();
        }
        static void Main(string[] args)
        {
            bool Exit = false;

            do
            {
                Console.WriteLine("What do you want to do?");
                Console.WriteLine("1 = Add");
                Console.WriteLine("2 = Sum");
                Console.WriteLine("3 = Subtract");
                Console.WriteLine("4 = Multiply");
                Console.WriteLine("5 = Power");
                Console.WriteLine("6 = Factorial");
                Console.WriteLine("7 = Exit");
                int input1 = Convert.ToInt32(Console.ReadLine());

                // Console.WriteLine("You choose " + input1);

                switch (input1)
                {
                case 1:
                    Console.WriteLine("You have chosen to add, I accept 2 numbers");
                    Console.WriteLine("Give me the first number");
                    int input2 = Convert.ToInt32(Console.ReadLine());
                    Console.WriteLine("The first number is " + input2 + ", What is your Second number?");
                    int input3 = Convert.ToInt32(Console.ReadLine());
                    Console.WriteLine("So you wish to add " + input2 + " + " + input3 + " together");
                    Console.WriteLine("Your result is " + Calculator.Add(input2, input3));
                    Console.ReadLine();
                    break;

                /*
                 * case 2
                 *
                 */
                case 3:
                    Console.WriteLine("You have chosen to subtract, I accept 2 numbers");
                    Console.WriteLine("Give me the first number");
                    int input4 = Convert.ToInt32(Console.ReadLine());
                    Console.WriteLine("The first number is " + input4 + ", What is your Second number?");
                    int input5 = Convert.ToInt32(Console.ReadLine());
                    Console.WriteLine("So you wish to subtract " + input4 + " - " + input5);
                    Console.WriteLine("Your result is " + Calculator.Subtract(input4, input5));
                    Console.ReadLine();
                    break;

                /*
                 * case 4
                 *
                 * case 5
                 *
                 * case 6
                 */
                case 7:
                    Exit = true;
                    break;

                default:
                    Console.WriteLine("Something Went Wrong");
                    break;
                }
            } while (Exit == false);
        }