using System;

using NCalc;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        Eval( "2 + 3" );

        Eval( "11 / 3" );

        Eval( "Truncate(11 / 3)" );

        Eval( "RANDOM(1000,2000)" );

        Eval( "RANDOM(20000,40000)*(Truncate(FARM_COUNT / 10) + 1)");

​

    }

    private static void Eval( string str )

    {

        Expression e = new Expression(str, EvaluateOptions.IgnoreCase);

        e.EvaluateFunction += NCalcExtensionFunctions;

        e.Parameters["FARM_COUNT" ] = 43;

        var result =  e.Evaluate();

        Console.WriteLine(str + " = " + result);

    }

    private static void NCalcExtensionFunctions(string name, FunctionArgs functionArgs)

    {

        if (name == "random")

        {

            if (functionArgs.Parameters.Length == 0)

            {

                functionArgs.Result = (float) new Random().NextDouble();

            }

            else if (functionArgs.Parameters.Length == 1)

            {

                var p0 = functionArgs.Parameters[0].Evaluate();

                if (p0 is int p0Int)

                {

                    functionArgs.Result = new Random().Next(0, p0Int+1);

                }

                else

                {

                    functionArgs.Result = (float)(new Random().NextDouble() *  (float)p0);

                }

            }

            else

            {

                var p0 = functionArgs.Parameters[0].Evaluate();

                var p1 = functionArgs.Parameters[1].Evaluate();

                if (p0 is int p0Int && p1 is int p1Int)

                {

                    functionArgs.Result = new Random().Next(p0Int, p1Int+1);

                }

                else

                {

                    functionArgs.Result = (float)((float)p0 + new Random().NextDouble() * ((float)p1 - (float)p0));

                }

            }

        }

    }

}