Module 7: Iterators That Wait

Practice Tasks

Complete these tasks to reinforce what you learned in this module.

Task 1: An iterator that awaits

Write an async iterator that waits briefly, then yields each number from 1 to count. Main consumes it with await foreach.

Expected Output:

1, 2 and 3 on separate lines.

Hint: static async IAsyncEnumerable<int> Ticks(int count), with await Task.Delay(10); before each yield return.

Starter Code:

task.cs

using System;
using System.Collections.Generic;
using System.Threading.Tasks;

class Program
{
    static async IAsyncEnumerable<int> Ticks(int count)
    {
        // Wait a moment, then hand back each number from 1 to count
        await Task.CompletedTask;
        yield break;
    }

    static async Task Main()
    {
        await foreach (var tick in Ticks(3))
        {
            Console.WriteLine(tick);
        }
    }
}

Task 2: Consume an async sequence

Add up everything an async sequence produces and print the total, then print done. Use await foreach.

Expected Output:

The sum 15, then `done`.

Hint: await foreach (var n in Values()) { total += n; } inside async Task Main.

Starter Code:

task.cs

using System;
using System.Collections.Generic;
using System.Threading.Tasks;

class Program
{
    static async IAsyncEnumerable<int> Values()
    {
        for (int i = 1; i <= 5; i++)
        {
            await Task.Delay(5);
            yield return i;
        }
    }

    static async Task Main()
    {
        // Sum everything Values() produces, print the total, then print done
    }
}