[C#] Implement new Concept Exercise: string-formatting

[ErikSchierboom]

This issue describes how to implement the string-formatting 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 basics of the Concept of String formatting in C#.

Learning objectives

• Know how to use the ToString() method to convert any object to a string.
• Know how to use string interpolation on values of any type.
• Know how to use default format strings to convert to standard output formats.
• Know how to use custom format strings to convert to custom output formats.
• Know that string.Format underlies string interpolation.
• Know of the StringBuilder type and when to use it.
• Know that string interpolation can interpolate any expression.

Out of scope

Nothing.

Concepts

This Concepts Exercise's Concepts are:

• string-formatting: know how to use the ToString() method to convert any object to a string; know how to use string interpolation on values of any type; know how to use default format strings to convert to standard output formats; know how to use custom format strings to convert to custom output formats; know that string.Format underlies string interpolation; know of the StringBuilder type and when to use it; know that string interpolation can interpolate any expression.

Prequisites

This Concept Exercise's prerequisites Concepts are:

• strings: strings will be formatted.
• inheritance: knowing that each class derives from object and thus has built-in methods.

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

Resources to refer to

Hints

• String interpolation: tutorial on how to use string interpolation.
• Formatting types: the available format types to use.
• Standard numeric format strings: lists the standard numeric format strings.
• Custom numeric format strings: describes how to define custom numeric format strings.
• Standard date and time format strings: lists the standard date and time format strings.
• Custom date and time format strings: describes how to define custom date and time format strings.
• String builder: shows how to use the string builder.

After

• String interpolation: tutorial on how to use string interpolation.
• Formatting types: the available format types to use.
• Standard numeric format strings: lists the standard numeric format strings.
• Custom numeric format strings: describes how to define custom numeric format strings.
• Standard date and time format strings: lists the standard date and time format strings.
• Custom date and time format strings: describes how to define custom date and time format strings.
• String builder: shows how to use the string builder.
• String interpolation - in-depth: in-depth examination of string interpolation, including the generated IL code.
• String interpolation - advanced: advanced tutorial on string interpolation, includes the FormattableString class.

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]

Please have a look at the instructions.

This is based on Elixir's strings exercise.

Tasks 1 and 3 push towards string interpolation.

Task 2 pushes towards string.Format() and verbatim strings.

[ErikSchierboom]

Yes, I like it! 👍

[mikedamay]

closed with PR #1871