A record with an operator in C#
C# interview exercise on Classes & Records, 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 Money as a record with Amount (int) and Currency (string). Adding two Money values with + returns a new Money; different currencies throw InvalidOperationException. Records are immutable: a changed copy is made with a `with` expression.
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.