using System;

using System.Collections.Generic;

using System.Linq;

using System.IO;

using Newtonsoft.Json;

using Newtonsoft.Json.Linq;

​

namespace Exam1JesperZachrisson

{

    class Statistics

    {

        public static dynamic DescriptiveStatistics(int[] source)

        {

            if (source == null)

                {

                    throw new System.ArgumentNullException("Parameter cannot be null", "source");

                }

            if (source.Length == 0)

                {

                    throw new System.InvalidOperationException("Sequence contains no elements");

                }

                    int maximum = Maximum(source);

                    int minimum = Minimum(source);

                    double mean = Mean(source);

                    double median = Median(source);

                    int range = Range(source);

                    int[] mode = Mode(source);

                    double standardDeviation = StandardDeviation(source);

​

                    return $"Maximum: {maximum}\n" + 

                           $"Minimum: {minimum}\n" + 

                           $"Mean: {mean:f1}\n" + 

                           $"Median: {median:f1}\n" + 

                           $"Range: {range}\n" + 

                           $"Mode: {string.Join(", ", mode)}\n" +

                           $"Standard Deviation: {Math.Truncate(standardDeviation * 10) / 10}";

        }

        public static int Maximum(int[] source)

        {   

            // if (source == null)

            //     {

            //         throw new System.ArgumentNullException("Parameter cannot be null", "source");

            //     }

            // if (source.Length == 0)

            //     {

            //         throw new System.InvalidOperationException("Sequence contains no elements");

            //     }

            return source.Max();

        }

​

        public static int Minimum(int[] source)

        {

            // if (source == null)

            //     {

            //         throw new System.ArgumentNullException("Parameter cannot be null", "source");

            //     }

            // if (source.Length == 0)

            //     {

            //         throw new System.InvalidOperationException("Sequence contains no elements");

            //     }

            return source.Min();

        }

​

        public static double Mean(int[] source)

        {

            // if (source == null)

            //     {

            //         throw new System.ArgumentNullException("Parameter cannot be null", "source");

            //     }

            // if (source.Length == 0)

            //     {

            //         throw new System.InvalidOperationException("Sequence contains no elements");

            //     }

            return source.Average();

        }

​

        public static double Median(int[] source)

        {

            // if (source == null)

            //     {

            //         throw new System.ArgumentNullException("Parameter cannot be null", "source");

            //     }

            // if (source.Length == 0)

            //     {

            //         throw new System.InvalidOperationException("Sequence contains no elements");

            //     }

            int[] copiedArr = source.OrderBy(x => x).ToArray();

            // Finding middle of array.

            int middle = copiedArr.Length / 2;

​

            if (copiedArr.Length % 2 == 0)

            { 

            // If there are two middle numbers, return mean of given numbers.  

              return ((double)copiedArr[middle - 1] + copiedArr[middle]) / 2;

            } 

            else 

            {

                return copiedArr[middle];

            }       

        }

​

        public static int Range(int[] source)

        {

            // if (source == null)

            //     {

            //         throw new System.ArgumentNullException("Parameter cannot be null", "source");

            //     }

            // if (source.Length == 0)

            //     {

            //         throw new System.InvalidOperationException("Sequence contains no elements");

            //     }

​

            return source.Max() - source.Min();

        }

​

        public static int[] Mode(int[] source)

        {

            // if (source == null)

            //     {

            //         throw new System.ArgumentNullException("Parameter cannot be null", "source");

            //     }

            // if (source.Length == 0)

            //     {

            //         throw new System.InvalidOperationException("Sequence contains no elements");

            //     }

​

            Dictionary<int, int> modeTable = new Dictionary<int, int>();

            foreach( int num in source ) {

            if ( modeTable.ContainsKey(num) )

                modeTable[num] = modeTable[num] + 1;

                else

                modeTable[num] = 1;

            }

​

                var modeList = new List<int>();

​

                var orderedList = modeTable.OrderBy(x => x.Value);

                var highestOccurrence = orderedList.ElementAt(orderedList.Count()-1).Value;

​

                var mode = orderedList

                .Where(kvp => kvp.Value == highestOccurrence)

                .ToDictionary(kvp => kvp.Key, kvp => kvp.Value);

​

                foreach(var item in mode.Keys)

                {

                    modeList.Add(item);

                }

​

                modeList = modeList.OrderBy(i => i).ToList();

​

                return modeList.ToArray();

        }

        public static double StandardDeviation(int[] source)

        {

            // if (source == null)

            //     {

            //         throw new System.ArgumentNullException("Parameter cannot be null", "source");

            //     }

            // if (source.Length == 0)

            //     {

            //         throw new System.InvalidOperationException("Sequence contains no elements");

            //     }

​

            double average = source.Average(); 

​

            var differences = source.Select(x => x - average).ToArray();

            var multiplyDifferences = differences.Select(x => x * x);

​

            var differencesAverage = multiplyDifferences.Average();

            var standardDev = Math.Sqrt(differencesAverage);

​

            return standardDev;

​

        }

    }

}

​