public class Integration2 {

    public static void main (String[] argv)
    {
        // We'll compute f(x) at x=1, 2, ..., 10 and put that in a graph.
        Function F = new Function ("f");

        // Notice: we are computing f(1), f(2), ..., and NOT f(d), f(2d), ...
        for (double x=1; x<=10; x+=1) {
            // Our method compute_f() does all the dirty work.
            double f = compute_f (x);
            F.add (x, f);
            System.out.println ("x=" + x + "  f(x)=" + f);
        }

        // Display.
        F.show ();
    }
    

    static double compute_f (double x)
    {
        // The value of d is fixed throughout.
        double d = 0.01;

        // Initial value is assumed known:
        double f = 0;

        // Compute for x-values in [0,10]. We are now using a variable called z.
        // Notice: goes over the range 0.01 up through x (which is input to the method).
        for (double z=0.01; z<=x; z+=0.01) {
            // We are given g, so we can compute it.
            double g = 6 * z;

            // Find the new value at f(z+d) that becomes the new f.
            f = f + d * g;

            // No need to print intermediate values.
        }

        // Return f(x)
        return f;
    }

}