Make a type sortable with IComparable in C#
C# interview exercise on Classes & Records, 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 SemVer, a record with Major, Minor and Patch. Parse("1.2.3") builds one and throws FormatException for anything that is not three integers separated by dots. CompareTo orders by Major, then Minor, then Patch, so 1.10.0 comes after 1.2.0. ToString gives "1.2.3" back.
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.