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; 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.
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