Implement new Concept Exercise: memory-allocation

[ErikSchierboom]

This issue describes how to implement the memory-allocation concept exercise for the C# track.

Getting started

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 up on 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.

Goal

The goal of this exercise is to teach the student the Concept of Memory Allocation in C#.

Learning objectives

• Know what the stack and heap are.
• Know what the garbage collector is.
• Know how the stack and heap are different.
• Know what the large object heap is.
• Know what reference and value types are.
• Know how reference and value types relate to the stack and heap.

Out of scope

• Memory locality.
• Memory pooling.
• Span<T> and Memory<T>
• stackalloc
• unsafe code.
• fixed statements.
• Defensive copies and readonly semantics.
• Discussion of profiling tools (referring to them is fine).

Concepts

This Concepts Exercise's Concepts are:

• memory-allocation: know what the stack and heap are; know what the garbage collector is; know how the stack and heap are different; know what the large object heap is; know what reference and value types are; know how reference and value types relate to the stack and heap.

Any data types used in this exercise (e.g. strings) should also be added as prerequisites.

Prequisites

This Concept Exercise's prerequisites Concepts are:

• classes: know how to define and work with classes.
• structs: know how to define and work with structs.

Resources to refer to

Hints

• Value types: introduction to value types.
• Reference types: introduction to reference types.
• Stack versus heap: how the stack and heap work.

After

• Value types: introduction to value types.
• Reference types: introduction to reference types.
• Stack versus heap: how the stack and heap work.
• Value types vs reference types: in-depth comparison between value and reference types
• Garbage collection: how garbage collection works in C#.
• Large Object Heap: what the Large Object Heap is.
• Garbage collection performance: in-depth look into garbage collection performance.

Representer

This exercise does not require any specific representation logic to be added to the representer.

Analyzer

This exercise does not require any specific analyzer logic to be added to the analyzer.

Implementing

To implement this exercise, please follow these instructions.

Help

If you have any questions while implementing the exercise, please post the questions as comments in this issue.

[mikedamay]

Should we consider closing this issue and combining the concept with structs? Exposure to the subtleties of heap vs. stack, large object heap, garbage collection might fit more easily in structs' after.md.

[ErikSchierboom]

This is a tough call I feel. The reason why I had it as a separate exercise is because I think there is quite a bit of information here. It might be that the after.md of the structs exercise could be a bit dense. Maybe we could leave it open for now but still explore if we could add this information in the structs exercise's after.md file.

[mikedamay]

Sounds good. Part of my reasoning was the difficulties of setting puzzles. It's also related to a point I was trying to make under Exercism's Ambition here.

[ErikSchierboom]

Yes, I read that! It is an excellent point.

[mikedamay]

• Contrast C# developers' attitude to out-of-memory conditions with those of lower level languages like C.