/*
 * Aresh Saharkhiz
 * saharkiz@gmail.com
 * Associate Professor / Mapua Institute of Technology / Philippines
 */

using System;

// Introduction to Software Testing, www.introsoftwaretesting.com
// Authors: Paul Ammann & Jeff Offutt
// Chapter 2, section 2.3, slide 15


internal class stats
{

    // Example for data flow. Has some issues.
    // The calculation of mean fails with an empty numbers list.
    // The calculation of var fails with a numbers list of length one.
    public static void computeStats(int[] numbers)
    {
        int length = numbers.Length;
        double med, @var, sd, mean, sum, varsum;

        sum = 0.0;
        for (int i = 0; i < length; i++)
        {
            sum += numbers[i];
        }
        med = numbers[length / 2];
        mean = sum / (double)length;

        varsum = 0.0;
        for (int i = 0; i < length; i++)
        {
            varsum = varsum + ((numbers[i] - mean) * (numbers[i] - mean));
        }
        @var = varsum / (length - 1);
        sd = Math.Sqrt(@var);

        Console.WriteLine("median:             " + med);
        Console.WriteLine("variance:           " + @var);
        Console.WriteLine("standard deviation: " + sd);
    }

    public static void Main(string[] argv)
    { // Driver method for computeStats
        int[] numbers1 = new int[] { 1, 5, 7, 9, 10, 15 };
        Console.WriteLine("TEST 1");
        Console.WriteLine("Input: " + numbers1.ToString());
        computeStats(numbers1);

        Console.WriteLine("\n----------------------------------");
        int[] numbers2 = new int[] { 42 };
        Console.WriteLine("TEST 2");
        Console.WriteLine("Input: " + numbers2.ToString());
        computeStats(numbers2);

        Console.WriteLine("\n----------------------------------");
        int[] numbers3 = new int[] { };
        Console.WriteLine("TEST 3");
        Console.WriteLine("Input: " + numbers3.ToString());
        try
        { // Expect ArrayIndexOutOfBoundsException
            computeStats(numbers3); // Throws ArrayIndexOutOfBoundsException
        }
        catch (System.IndexOutOfRangeException)
        {
            Console.WriteLine("ArrayIndexOutOfBoundsException thrown.");
        }

        // This doesn't compile
         //Console.WriteLine ("\n----------------------------------");
         //int [] numbers4;
         //Console.WriteLine("TEST 4");
         //Console.WriteLine("Input: " + numbers4.ToString());
         //computeStats (numbers4);
    }

}