A lazy extension method in C#
C# interview exercise on Delegates & Iterators, difficulty 3 of 3. Solve it in the editor beside a worked example, or cold in Interview mode with the example hidden; the tests run the moment you do.
Write Chunked(size), an extension method on IEnumerable<T> that yields lists of up to size items. It must be lazy and work for any sequence, including an endless one, so it cannot count the items or index into them. (LINQ's Chunk does this; write it yourself.)
Each exercise pairs a worked example with a twin problem to solve in a real editor; the tests run the moment you do. Interview mode hides the example: solve it from memory, without the hint or the solution, and it counts as solved cold. Progress is saved in your browser, and in your account if you sign in.