Example 2: Integral of exp(-x) from 0 to infinity

using System;
using Imsl.Math;

public class QuadratureEx2 : Quadrature.IFunction
{
	public double F(double x)
	{
		return Math.Exp(- x);
	}


	public static void  Main(String[] args)
	{		
		Quadrature q = new Quadrature();
		Quadrature.IFunction fcn = new QuadratureEx2();
		double result = q.Eval(fcn, 0.0, Double.PositiveInfinity);
		
		double expect = 1.0;
		Console.Out.WriteLine("result = " + result);
		Console.Out.WriteLine("expect = " + expect);
	}
}

Output

result = 0.999999999999999
expect = 1