Passing an IEnumerable of Numeric Values as a parameter to method

Question

I'm playing around with a very simple program to take an array of doubles and return the standard deviation. This part worked but I wanted to make the code more reusable. I would like to make it so the method can accept a parameter of any type that could be considered numeric and return the standard deviation instead of hardcoding a double type (like I initially did in this program). How does one go about this and what is the proper term for it?

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;


    namespace ConsoleApplication5
    {
        class Program
        {
            static void Main(string[] args)
            {
                double[] avg = { 3.4, 55.6, 10.0, 4.5, 2, 2 };
                double x = avg.Average();
                //first round of testing
                Console.WriteLine("The average of the first array is below ");
                Console.WriteLine(x);
                Console.WriteLine("below should be the standard deviation!");
                Console.WriteLine(CalculateStandardDeviation(avg));
                Console.ReadLine();
                int[] intAvg = { 4, 3, 5, 6, 2 };
                double secondAvg = intAvg.Average();
                Console.WriteLine("The average of the second array is below ");
                Console.WriteLine(secondAvg);
                //this is where the error is happening
                //CalculateStandardDeviation(secondAvg);

            }
            //this is where I tried to make the query more reusable
            public static double CalculateStandardDeviation(IEnumerable<double> values)
            {

                double avg = values.Average();
                double sum = 0;
                foreach (double d in values)
                {
                    sum += Math.Pow((d - avg), 2);

                }

                return Math.Pow(sum / (values.Count() - 1),.5);

            }
        }
    }

Answer 1

You could use something like this:

public static decimal CalculateStandardDeviation<T>(IEnumerable<T> values)
{
    IEnumerable<decimal> decimalValues = values.Select(v => Convert.ToDecimal(v));

    decimal result = 0;

    // calculate standard deviation on decimalValues

    return result;
}

It will throw an exception if values contains values that can't be converted to a decimal, but will work if the values are of an appropriate type, and I think that makes perfect sense.