using System;
using System.Text;
using System.Runtime.InteropServices;
using NagLibrary;

public class NagD01Functions
{
    public static void Main()
    {
        nag_declarations.nag_1d_quad_gen_1_f_DELEGATE F = new nag_declarations.nag_1d_quad_gen_1_f_DELEGATE(f);
        nag_declarations.Nag_QuadProgress qp = new nag_declarations.Nag_QuadProgress();
        double a = 0.0;
        double b = Math.PI * 2.0;
        double epsabs = 0.0;
        double epsrel = 0.0001;
        int max_num_subint = 200;
        double result = 0.0;
        double abserr = 0.0;
        nag_declarations.Nag_User user_comm = new nag_declarations.Nag_User();
        nag_declarations.NagError fail = new nag_declarations.NagError();
        fail.message = new byte[512];
        Encoding enc = Encoding.ASCII;

        /* nag_1d_quad_gen_1 (d01sjc).
         * One-dimensional adaptive quadrature, allowing for badly
         * behaved integrands, thread-safe
         */
        nag_declarations.nag_1d_quad_gen_1(F, a, b, epsabs, epsrel, max_num_subint, ref result,
                                           ref abserr, ref qp, ref user_comm, ref fail);
        if (fail.code != 0)
        {
            Console.WriteLine("Error from nag_1d_quad_gen_1 (d01sjc):");
            Console.WriteLine(enc.GetString(fail.message));
        }
        else
        {
            Console.WriteLine("Approximation to the integral = {0, 9:f5}", result);
            Console.WriteLine("Estimate of the absolute error = {0, 9:e2}", abserr);
            Console.WriteLine("Number of function evaluations = {0, 4:d}", qp.fun_count);
            Console.WriteLine("Number of subintervals used = {0, 4:d}", qp.num_subint);
        }
    }

    public static double f(double x, ref nag_declarations.Nag_User comm)
    {
        double retval = 0;

        retval = (x * Math.Sin(x * 30.0) / Math.Sqrt(1.0 - x * x / (Math.PI * Math.PI * 4.0)));
        return retval;
    }
}