using System;

​

public class Program

{

    public static void Main()

    {

        string restart = "hello world";

        while (restart != "q")

        {

            start:

            Console.Clear();

        Console.WriteLine("Hello and Welcome to My Probability Calculator!  Please Choose an option from the menu!");

        Console.WriteLine("If you would like to calculate Factorial, please press 1.");

        Console.WriteLine("If you would like to calculate Decimal to Percent, please press 2.");

        Console.WriteLine("If you would like to calculate Percent to Decimal,, please press 3.");

        Console.WriteLine("If you would like to calculate the Mean of a list of numbers, please press 4.");

        Console.WriteLine("If you would like to calculate the Permutation, please press 5");

        Console.WriteLine("If you would like to calculate the Combination of a list of numbers, please press 6.");

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

        if (choice == 1)

        {

            Console.Clear();

        Console.WriteLine("Please enter a postive number to calculate the factorial of.");

        ulong input = ulong.Parse(Console.ReadLine());

        ulong output = fact(input);

        Console.WriteLine(output);

        Console.WriteLine("The factorial of " +input+ "! =" +output);

            if (input > 65)

        Console.WriteLine("We're sorry, the number exceeds the holding of the data type, Please choose a smaller number!");

            Console.WriteLine("Press q to quit or any other key to continue.");

                restart = Console.ReadLine();

                goto start;

        }

        else if (choice == 2)

        {

            Console.Clear();

        Console.WriteLine("If you would like to convert a decimal to a percent, please enter a number");

        Console.WriteLine("What decimal would you like to convert to percent?");

        double ans = double.Parse(Console.ReadLine());

        Console.WriteLine(ans + " =  " + DectoPer(ans));

            Console.WriteLine("Press q to quit or any other key to continue.");

                restart = Console.ReadLine();

                goto start;

        }

        else if (choice == 3)

        {

            Console.Clear();

        Console.WriteLine("If you would like to convert a percent to decimal, please enter a number");

        double ans = double.Parse(Console.ReadLine());

        Console.WriteLine(ans + " =  " + PertoDec(ans));

            Console.WriteLine("Press q to quit or any other key to continue.");

                restart = Console.ReadLine();

                goto start;

        }

        else if (choice == 4)

        {

            Console.Clear();

         Console.WriteLine("Please enter three numbers to calculate the mean of");

         double mean1 = double.Parse(Console.ReadLine());

         double mean2 = double.Parse(Console.ReadLine());

         double mean3 = double.Parse(Console.ReadLine());

         Console.WriteLine("okay, the mean of your three numbers is " +mean(mean1, mean2, mean3));

            Console.WriteLine("Press q to quit or any other key to continue.");

                restart = Console.ReadLine();

                goto start;

        }

        else if (choice == 5)

        {

            Console.Clear();

            Console.WriteLine("Please enter the amount of numbers you want in your set.");

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

         Console.WriteLine("Please now enter the amount of objects you want to choose from this set.");

         ulong o = ulong.Parse(Console.ReadLine());

         Console.WriteLine("From the numbers chosen, the perumuations of " +o+ " from " +n+ " is " +Perm(n, o));

        if (n > 65)

        if (o > 65)

        Console.WriteLine("We're sorry, the number exceeds the holding of the data type, Please choose a smaller number!");

            Console.WriteLine("Press q to quit or any other key to continue.");

                restart = Console.ReadLine();

                goto start;

        }

        else 

        {

            Console.Clear();

            Console.WriteLine("Please enter the amount of items you have.");

            ulong n1 = ulong.Parse(Console.ReadLine());

            Console.WriteLine("How many ways would like to have this set up?");

            ulong w = ulong.Parse(Console.ReadLine());

            Console.WriteLine(n1 + "C" + w + " = " + nCr(n1, w));

            if (n1 > 65)

            if (w > 65)

        Console.WriteLine("We're sorry, the number exceeds the holding of the data type, Please choose a smaller number!");

            Console.WriteLine("Press q to quit or any other key to continue.");

                restart = Console.ReadLine();

                goto start;

​

        }

        }

    }

​

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​

        static private ulong fact(ulong a) //Method to calculate factorial 

    {

        ulong factorial = 1;

        ulong i = 1;

        do

        {

            factorial = factorial * i;

            i++;

        }

        while (i <= a);

        return factorial;

    }

        static private double DectoPer(double a) //Method to calculate DectoPer

    {

        return a * 100;

    }

​

        static private double PertoDec(double a) //Method to calculate PertoDec

    {

        return a / 100;

    }

        static private double mean(double a, double b, double c) //Method to calculate Mean

        {

            double addition = a + b + c;

            double Mean = addition/3;

                return Mean;

    {

    }

        }

        static private ulong Perm(ulong n, ulong o) //Method to calculate Perumtation

    {

        ulong N = fact(n);

        ulong order = n - o;

        ulong Order = fact(order);

        ulong permutation = N / order;

        return permutation;

            {

            }

        }

        static private ulong nCr(ulong n, ulong o) // Method to calculate Combination

    {

        ulong nfact = fact(n);

        ulong ofact = fact(o);

        ulong nofact = fact(n - o);

        return nfact/((nofact) * (ofact));

        }

}

​

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