using System;

using System.Diagnostics;

using System.Threading.Tasks;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine(string.Empty);

        //WhatIsOutput1().Wait();

        Console.WriteLine(string.Empty);

        //WhatIsOutput2();

    }

​

    public async static Task WhatIsOutput1()

    {

        var stopWatch = new Stopwatch();

        stopWatch.Start();

        await PrintFunction(2d,'a');

        await PrintFunction(2d,'b');

        await PrintFunction(1d,'c');

        await PrintFunction(1d,'d');

        stopWatch.Stop();

        Console.WriteLine(string.Empty);

        Console.WriteLine($"Total time: {Math.Round(stopWatch.ElapsedMilliseconds / 1000d, 1)} seconds");

    }

​

    public static void WhatIsOutput2()

    {

        var stopWatch = new Stopwatch();

        stopWatch.Start();

        Task.WaitAll(PrintFunction(2d,'a'), PrintFunction(2d,'b'), PrintFunction(1d,'c'), PrintFunction(1d,'d'));

        stopWatch.Stop();

        Console.WriteLine(string.Empty);

        Console.WriteLine($"Total time: {Math.Round(stopWatch.ElapsedMilliseconds / 1000d, 1)} seconds");

    }

​

    public async static Task PrintFunction(double delay, char character)

    {

        await Task.Delay(TimeSpan.FromSeconds(delay));

        Console.Write(character);

    }

}