using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using NagCFunctionsAPI;

namespace E01BEC
{
    class Program
    {
 
        static void Main(string[] args)
        {
            double[] x = { 0.0, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, 12.0, 13.0 };
            double[] y = { 0, 0.841470985, 0.909297427, 0.141120008, -0.756802495, -0.958924275, -0.279415498, 0.656986599, 0.989358247, 0.412118485, -0.544021111, -0.999990207, -0.536572918, 0.420167037 };
            int m = x.Length;
            int n = 2 * m - 1;
            double[] d = new double[m];
            double[] px = new double[n];
            double[] pf = new double[n];

            NagError fail = new NagError();

            try
            {
                NagFunctions.e01bec(m, x, y, d, ref fail);

                switch (fail.code)
                {
                    case 11:
                        throw new Exception("On entry, n < 2.");

                    case 245:
                        throw new Exception("The values of x[r], for r = 0,1,...,m-1, are not in strictly increasing order.");

                    default:
                        break;
                }

            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }

            //fill px with values to be evaluated 
            for (int i = 0; i < m; i++)
            {
                px[2 * i] = x[i];
                if (i > 0)
                    px[2 * i - 1] = 0.5 * (x[i - 1] + x[i]);
            }

            if (fail.code == 0)
            {
                try
                {
                    NagFunctions.e01bfc(m, x, y, d, n, px, pf, ref fail);
                    switch (fail.code)
                    {
                        case 11:
                            throw new Exception("On entry, n < 2 or m < 1.");

                        case 245:
                            throw new Exception("The values of x[r], for r = 0,1,...,m-1, are not in strictly increasing order.");

                        case 246:
                            throw new Exception("At least one of the points px[i], for i= 0,1,...,n-1, lies outside the interval [x[0],x[m-1]], and the extrapolation was performed at all such points. Values computed at such points may be very unreliable.");

                        default:
                            break;
                    }
                }
                catch (Exception ex)
                {
                    Console.WriteLine(ex.Message);
                    
                }

                Console.WriteLine("Abscissa      Interpolated Values");
                for (int i = 0; i < n; i++)
                {
                    Console.WriteLine("{0} \t {1, 10:f4}", px[i], pf[i]);
                }
            }
        }
    }
}