using NCalc;

using System;

​

public class Program

{

    public static void Main(string[] args)

    {

        var expressions = new[]

        {

            "(353.05/([AmbientTemperature] + 273.15)) * (Exp(-0.034*(([Altitude] + [HubHeight])/ (([AmbientTemperature] + 273.15)))))",

            "(353.05/([Temperature])) * (Exp(-0.034*(([Altitude] + [HubHeight])/ (([Temperature])))))",

            "([TemperatureCoefficient]) * (Exp(-0.034*(([Altitude] + [HubHeight])/ (([Temperature])))))",

            "[TemperatureCoefficient] * [PressureCoefficient]"

        };

        foreach (string expression in expressions)

        {

            Expression myExpr = new Expression(expression);

            myExpr.Parameters["AmbientTemperature"] = -1;

            myExpr.Parameters["Altitude"] = 319;

            myExpr.Parameters["HubHeight"] = 80;

            myExpr.Parameters["Temperature"] = new Expression("[AmbientTemperature] + 273.15");

            myExpr.Parameters["TemperatureCoefficient"] = new Expression("353.05/[Temperature]");

            myExpr.Parameters["PressureCoefficient"] = new Expression("Exp(-0.034*(([Altitude]+[HubHeight])/[Temperature]))");

            System.Console.WriteLine(expression + " => " + myExpr.Evaluate());

            if (myExpr.Parameters.Count > 0)

            {

                foreach (var myExprParameter in myExpr.Parameters)

                {

                    Console.WriteLine("Parameter " + myExprParameter.Key +" => " + myExprParameter.Value.ToString());

                }

            }

        }

    }

}