I have an exercise in asynchronous programming like this: There are 4 Tasks: Task1, Task2, Task3, Task4. Task1 and Task2 run in parallel. Task3 is only run when either Task1 or Task2 completes. Task4 runs when all 3 previous tasks must be completed. This is how I do it, but my teacher asked me not to separate the function to handle Task.WaitAny() (in the picture is the waitAny() function), and not to use async in ContinueWith. Can someone help me?
Screenshot with code.

static async Task<int> waitAny()
{
    return Task.WaitAny(runTask1(), runTask2());
}

static void Main(string[] args)
{
    waitAny().ContinueWith( 
    async (_taskToContinue) => 
    {
        await runTask3();

        Task.WaitAll(runTask1(), runTask2(), runTask3());

        await runTask4();

    });

    Console.ReadKey();
}

CodePudding user response：

Would do it like this then.

    static void Main(string[] args)
    {
        var task1 = runTask1();
        var task2 = runTask2();

        Task.WhenAny(task1, task2).ContinueWith(task =>
        {
            var task3 = runTask3();

            Task.WaitAll(task1, task2, task3);

            var task4 = runTask4();
            task4.Wait();
        });
    }