implementing-a-concept-exercise.md

How to implement a C++ concept exercise

This document describes how to implement a concept exercise for the C++ track.

Please please please read the docs before starting. Posting PRs without reading these docs will be a lot more frustrating for you during the review cycle, and exhaust Exercism's maintainers' time. So, before diving into the implementation, please read the following documents:

• The features of v3.
• Rationale for v3.
• What are concept exercise and how they are structured?

Please also watch the following video:

• The Anatomy of a Concept Exercise.

As this document is generic, the following placeholders are used:

• <SLUG>: the slug of the exercise in kebab-case (e.g. calculator-conundrum).
• <NAME>: the name of the exercise in snake_case (e.g. calculator_conundrum).
• <CONCEPT_SLUG>: the slug of one of the exercise's concepts in kebab-case (e.g. anonymous-methods).

Before implementing the exercise, please make sure you have a good understanding of what the exercise should be teaching (and what not). This information can be found in the exercise's GitHub issue. Having done this, please read the [C++ concept exercises introduction][concept-exercises].

To implement a concept exercise, the following files must be added:

languages
└── cpp
    ├── concepts
    |   └── <CONCEPT_SLUG>
    |       ├── about.md
    |       └── links.json
    └── exercises
        └── concept
            └── <SLUG>
              ├── .docs
              │   ├── hints.md
              │   ├── instructions.md
              │   ├── introduction.md
              |   └── source.md (required if there are third-party sources)
              ├── .meta
              |   |── config.json
              │   ├── design.md
              │   ├── exemplar.cpp
              │   └── exemplar.h
              ├── CMakeLists.txt
              ├── <NAME>.cpp
              ├── <NAME>.h
              ├── <NAME>_test.cpp
              └── test
                  └── tests_main.cpp

Step 1: Add code files

The code files are track-specific and should be designed to help the student learn the exercise's concepts. The following C++ code files must be added (not necessarily in this order):

• <NAME>.h and <NAME>.cpp. the stub implementation files, which is the starting point for students to work on the exercise.
• CMakeLists.txt: the C++ project file.
• <NAME>_test.cpp: the test suite.
• .meta/exemplar.h and .meta/exemplar.cpp: an exemplar implementation that passes all the tests.
• test/tests_main.cpp: generates test main from test library

Step 2: Add documentation files

How to create the files common to all tracks is described in the how to implement a concept exercise document.

Step 3: Update list of implemented exercises

• Add the exercise to the list of implemented exercises.

Inspiration

When implementing this exercise, it can be very useful to look at already implemented C++ exercises.

Help

If you have any questions regarding implementing the exercise, please post them as comments in the exercise's GitHub issue.