interview-async-await

 public class Class1
    {
        public async Task Method1()
        {
           await Task.Delay(100000);
           Console.WriteLine($"Class1.Method1");
        }
        public async Task Method2()
        {
           await Task.Delay(200000);
           Console.WriteLine($"Class1.Method2");
        }

        public async Task Method3()
        {
           await Task.Delay(300000);
           Console.WriteLine($"Class1.Method3");
        }
    }
	
	
--------------
public class Class2
    {
        public async Task Method1()
        {
            Console.WriteLine($"Class2.Method1  ");
        }
        public async Task Method2()
        {
            Console.WriteLine($"Class2.Method2 ");
        }

        public async Task Method3()
        {
            Console.WriteLine($"Class2.Method3 ");
        }
    }	
		
---------------------------------		
async Task MainAsync()
{
	var executor = new Executor();
	await executor.DoWork();
}

---------------

static void Main(string[] args)
        {
            Console.WriteLine($"Hello World! ");
            MainAsync().GetAwaiter().GetResult();
            Console.WriteLine($"Bye Bye World! ");
            Console.ReadLine();
        }
		

###################################		
Case 1:
----------	
 public class Executor
    {
        Class1 cls1;
        Class2 cls2;
        public Executor()
        {
            cls1 = new Class1();
            cls2 = new Class2();
        }
        public async Task DoWork()
        {
            await cls1.Method1();
            await cls1.Method2();
            await cls1.Method3();

            await cls2.Method1();
            await cls2.Method2();
            await cls2.Method3();
            Console.WriteLine($"Do work done.");
        }
    }


###################################		
Case 2:
----------	
 public class Executor
    {
        Class1 cls1;
        Class2 cls2;
        public Executor()
        {
            cls1 = new Class1();
            cls2 = new Class2();
        }
        public async Task DoWork()
        {
		 List<Task> tasks = new List<Task>();
             tasks.Add(cls1.Method1());
            tasks.Add(cls1.Method2());
            tasks.Add(cls1.Method3());

            tasks.Add(cls2.Method1());
            tasks.Add(cls2.Method2());
            tasks.Add(cls2.Method3());
            
            await Task.WhenAll(tasks);
            Console.WriteLine($"Do work done.");
        }
    }

###################################		





Case 3:
----------	
 public class Executor
    {
        Class1 cls1;
        Class2 cls2;
        public Executor()
        {
            cls1 = new Class1();
            cls2 = new Class2();
        }
        public async Task DoWork()
        {
		 List<Task> tasks = new List<Task>();
             tasks.Add(cls1.Method1());
            tasks.Add(cls1.Method2());
            tasks.Add(cls1.Method3());

            tasks.Add(cls2.Method1());
            tasks.Add(cls2.Method2());
            tasks.Add(cls2.Method3());
            
            await Task.WhenAny(tasks);
            Console.WriteLine($"Do work done.");
        }
    }