Example: The shape preserving cubic spline interpolant

A cubic spline interpolant to a function is computed consistent with the concavity of the data. The spline value at 0.05 is printed. 
using System;
using Imsl.Math;

public class CsShapeEx1
{
    public static void  Main(String[] args)
    {
        double[] x = new double[]{0.00, 0.10, 0.20, 0.30, 0.40,
                                     0.50, 0.60, 0.80, 1.00};
        double[] y = new double[]{0.00, 0.90, 0.95, 0.90, 0.10, 
                                     0.05, 0.05, 0.20, 1.00};
        
        CsShape cs = new CsShape(x, y);
        double csv = cs.Eval(0.05);
        Console.Out.WriteLine("The computed cubic spline value at " +
                              "point .05 is " + csv);
    }
}

Output

The computed cubic spline value at point .05 is 0.55823122286482
Link to C# source.