An endless iterator in C#
C# interview exercise on Delegates & Iterators, difficulty 2 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 Fibonacci(), an iterator that yields 0, 1, 1, 2, 3, 5, ... forever. It never finishes, and that is fine: the caller decides how much to take.
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.