using System;

using System.IO;

​

​

public class Program

{

    // Don't change Main

    public static void Main()

    {

        var foo = new Foo(1.5);

        foo.LogMessage("Hello world");

        var result1 = foo.DoCalc(1, 2);

        var result2 = foo.higherOrderCalculation(3, 4);

    }

public class Foo

{

    public double StartValue { get; }

    public Foo(double startValue)

    {

        StartValue = startValue;

    }

​

    public double DoCalc(double value1, double value2)

    {

        return value1 + value2 / StartValue;

    }

​

    public double higherOrderCalculation(double one, double two)

    {

        return one + two;

    }

​

    public async void LogMessage(string message, bool logToFile = true, bool logToConsole = true)

    {

        message = string.Format($"{DateTimeOffset.Now.ToString()} -> {message}");

        if(logToConsole)

            Console.WriteLine(string.Format(message));

        if(logToFile)

            await File.AppendAllTextAsync($"logfile{DateTime.Now.ToString("yyyy-MM-dd")}.log", $"{message}{Environment.NewLine}");

    }

}

​

​

}