using System;

public class Program

{

    public static void Main()

    {       

        SelectMode(CollectNumbers());

    }

    public static Collector CollectNumbers()

    {

        Console.WriteLine("Enter the length of the numbers:");

        return new Collector(int.Parse(Console.ReadLine()));

    }

    public static void SelectMode(Collector collector)

    {

        Console.WriteLine("Select Mode of The Program:");

        Console.WriteLine("1. Print some of statistical values.");

        Console.WriteLine("2. Determine whether a value is outlier or not.");

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

        switch (chosen) {

            case 1:

                StatisticalMode(collector);

                break;

            case 2:

                OutlierCheckerMode(collector);

                break;

            default:

                NotFoundMode(collector);

                break;

        }

    }

    public static void OutlierCheckerMode(Collector collector)

    {

        Console.WriteLine("Enter the value:");

        (new OutlierChecker(collector)).Is(double.Parse(Console.ReadLine())).PrintResults();

    }

    public static void StatisticalMode(Collector collector)

    {

        (new StatisticsOperations(collector)).PrintStatisticalValues();

    }

    public static void NotFoundMode(Collector collector)

    {

        Console.WriteLine("You have selected a wrong mode.");

        SelectMode(collector);

    }

}

​

public class Collector

{

    private double[] numbers;

    public Collector(int counter)

    {

        this.numbers = new double[counter];

        for (int i = 0; i < counter; i++) {

            Console.WriteLine("Enter the {0} number:", i + 1);

            this.numbers[i] = double.Parse(Console.ReadLine());

        }

    }

    public void Sort()

    {

        Array.Sort(this.numbers);       

    }

    public double[] GetNumbers()

    {

        return this.numbers;

    }

    public double GetNumber(int index)

    {

        return this.numbers[index];

    }

    public int GetLength()

    {

        return this.numbers.Length;

    }

    public double Sum()

    {

        double sum = 0;

        foreach (var item in this.GetNumbers()) {

            sum += item;

        }

        return sum;

    }

    public double Average()

    {

        return this.Sum() / this.GetLength();

    }

    public double GreatestNumber()

    {

        double greatest = this.GetNumber(0);

        foreach (var item in this.GetNumbers()) {

            if (item > greatest) {

                greatest = item;

            }

        }

        return greatest;

    }

    public double SmallestNumber()

    {

        double smallest = this.GetNumber(0);

        foreach (var item in this.GetNumbers()) {

            if (item < smallest) {

                smallest = item;

            }

        }

        return smallest;

    }

    public double Percentile(int p)

    {

        if (p >= 100) {

            return this.GreatestNumber();

        }

        double rank = (p * (this.GetLength() + 1)) / 100.0d;

        double lower = this.GetNumber((int) Math.Floor(rank) - 1);

        double upper = this.GetNumber((int) Math.Floor(rank));

        return lower + (upper - lower) * (rank - Math.Floor(rank));

    }

}

​

public class OutlierChecker

{

    private Collector collector;

    protected bool results = false;

    public OutlierChecker(Collector collector)

    {

        this.collector = collector;

        this.collector.Sort();

    }

    public OutlierChecker Is(double number)

    {

        double outlier = 0;

        double q1 = this.collector.Percentile(25);

        double q2 = this.collector.Percentile(50);

        double q3 = this.collector.Percentile(75);

        double iqr = q3 - q1;

        double max = q1 - (1.5 * iqr);

        double min = q3 + (1.5 * iqr);

        foreach (var item in this.collector.GetNumbers()) {

            if ((item < max || item > max) && outlier < item) {

                outlier = item;

            }

        }

        if (outlier == number) {

            this.results = true;

        }

        return this;

    }

    public void PrintResults()

    {

        if (this.results) {

            Console.WriteLine("Your entered number is an outlier.");

        } else {

            Console.WriteLine("Your entered number isn't an outlier");

        }

    }

}

​

public class StatisticsOperations

{

    private Collector collector;

    public StatisticsOperations(Collector collector)

    {

        this.collector = collector;

        this.collector.Sort();

    }

    public double Median()

    {

        return this.collector.GetNumber(this.collector.GetLength() / 2);

    }

    public double Mode()

    {

        double number = this.collector.GetNumber(0);

        double mode = number;

        int count = 1;

        int countMode = 1;

        foreach (var item in this.collector.GetNumbers()) {

            if (item == number) {

                count++;

            } else {

                if (count > countMode) {

                    countMode = count;

                    mode = number;

                }

                count = 1;

                number = item;

            }

        }

        return mode;

    }

    public double Range()

    {

        return this.collector.GreatestNumber() - this.collector.SmallestNumber();

    }

    public double StandardDivision()

    {

        double result = 0;

        foreach (var item in this.collector.GetNumbers()) {

            result += Math.Pow(item - this.collector.Average(), 2);

        }

        return Math.Sqrt(result / this.collector.GetLength());

    }

    public double SummationOfDivisions()

    {

        double result = 0;

        foreach (var item in this.collector.GetNumbers()) {

            result += Math.Pow(item - this.collector.Average(), 2);

        }

        return result;

    }

    public void PrintStatisticalValues()

    {

        Console.WriteLine("Median = {0}", this.Median());

        Console.WriteLine("Mode = {0}", this.Mode());

        Console.WriteLine("Range = {0}", this.Range());

        Console.WriteLine("Standard Division = {0}", this.StandardDivision());

        Console.WriteLine("Summation of Divisions = {0}", this.SummationOfDivisions());

        Console.WriteLine("Quartile 1 = {0}", this.collector.Percentile(25));

        Console.WriteLine("Quartile 2 = {0}", this.collector.Percentile(50));

        Console.WriteLine("Quartile 3 = {0}", this.collector.Percentile(75));

        Console.WriteLine("Percentile 20 = {0}", this.collector.Percentile(20));

    }

}