using static System.Math;

namespace lab2
{

    class Program
    {
        static int fact(int i)
        {
            return i == 1 || i == 0 ? 1 : fact(i - 1) * i;
        }
        static double[] takeY(double x)
        {
            int n = 0;
            const double exp = 1e-6;
            double element, nextElement;
            while (true)
            {
                element = (Pow(-1, n) * Pow(x, 2 * n)) / fact(n);
                nextElement = (Pow(-1, n + 1) * Pow(x, 2 * (n + 1))) / fact(n + 1);
                n++;
                if (Abs(nextElement - element) < exp) break;
            }
            return new double[]{ Round(element, 8), n };
        }
        static bool isTarget(double x, double y, double R1, double R2)
        {
            return
            (
            ((x * x + y * y) < (R1 * R1) && x < 0 && y > 0)
            ||
            ((x * x + y * y) > (R1 * R1) && (x * x + y * y) < (R2 * R2) && x > 0 && y < 0)
            ?
            true
            :
            false
            );
        }
        static string center<T> (T value, int width)
        {
            string val = value.ToString();
            int l = (width - val.Length);
            return (new string(' ', (l + 1)/2)) + val + (new string(' ', l/2));

        }
        static double takeFunctionValue(double x, double R)
        {
            double y;

            if (x <= -3) y = (x + 3) / 2.0;
            else if (x <= 0) y = System.Math.Sqrt(System.Math.Pow(R, 2) - System.Math.Pow(x, 2));
            else if (x <= 6)
                y = x/6.0 * R;
            else y = (x - 6) / 2.0;

            return y;
        }
        static void Main(string[] args)
        {
            System.Console.Write("Task 3.1\nEnter xs, xe, dx and R: ");
            string[] splitedStr = System.Console.ReadLine().Split(" ");
            double xs = double.Parse(splitedStr[0]),
                   xe = double.Parse(splitedStr[1]),
                   dx = double.Parse(splitedStr[2]),
                    R = double.Parse(splitedStr[3]);
            System.Console.WriteLine("|" + center<string>("F(x)", 10) + "|" + center<string>("x", 10) + "|");
            while (xs <= xe){
                double y = System.Math.Round(takeFunctionValue(xs, R), 2);
                System.Console.WriteLine("|" + center<double>(y, 10) + "|" + center<double>(xs, 10) + "|");
                xs += dx;
            }
            /*
            System.Console.Write("Task 3.2\n");
            System.Console.Write("Enter R1 and R2: ");
            splitedStr = System.Console.ReadLine().Split(" ");
            double R1 = double.Parse(splitedStr[0]),
                   R2 = double.Parse(splitedStr[1]);

            for (uint i = 0; i < 5; i++){
                System.Console.Write("Enter x, y: ");
                splitedStr = System.Console.ReadLine().Split(" ");
                double  x = double.Parse(splitedStr[0]),
                        y = double.Parse(splitedStr[1]);
                System.Console.WriteLine(isTarget(x, y, R1, R2) ? "True" : "False");
            }
            */
            System.Console.Write("Task 3.2\n");
            System.Console.Write("Enter xs, xe and dx: ");
            splitedStr = System.Console.ReadLine().Split(" ");
            xs = double.Parse(splitedStr[0]);
            xe = double.Parse(splitedStr[1]);
            dx = double.Parse(splitedStr[2]);

            System.Console.WriteLine("|" + center<string>("F(x)", 20)
                                         + "|" + center<string>("x", 10)
                                         + "|" + center<string>("n", 10) + "|");

            while (xs <= xe) {
                double[] y = takeY(xs);
                System.Console.WriteLine("|" + center<double>(y[0], 20)
                                             + "|"
                                             + center<double>(xs, 10)
                                             + "|" + center<double>(y[1], 10) + "|");
                xs += dx;

            }
        }
    }
}