Scheme vs C#

Scheme syntax is extremely regular and easy to pick up. A formal specification of the syntax fits onto just a few pages; it can be introduced informally in a paragraph or two. Students are not distracted by remembering how to write if statements or loops or even operator precedence because every syntactic follows the same pattern.

Ultimately, everything looks something like this:

(func a b c)

This includes not only user-defined functions but even control flow:

(if cond then-clause else-clause)

or even primitive operations like define and set:

(define foo 10)
(set! foo 11)

This means that nothing really has special syntactic treatment in the language. There are essentially no weird edge-cases to memorize, and different concepts are given a more equal weight in the language. (Unlike Algol-like languages which tend to given undue weight to loops and assignment statements, for example.)

Scheme has far less built into the language itself, helping students see that things like OOP are not magical: they are just patterns for organizing code. Everything in Scheme is built up from a very small set of primitives which compose in a natural and intuitive fashion.

Having a language that does not accord many things special status helps keep students open minded. This will help students later go between different languages and paradigms from procedural to object-oriented to functional.

Scheme teaches the important, fundamental ideas immediately without the distraction of unnecessary syntax or language features.

GNU/Linux, OS X, and Windows versions available.

There is a set of very strong textbooks introducing CS and programming using Scheme. These books are available for free online.

The most famous example--and one of the most famous CS books full stop--is Structure and Interpretation of Computer Programs usually known as SICP. This book introduces fundamental ideas in computer science and covers an incredible amount of material quickly and clearly without requiring any prior knowledge.

However, some people find SICP a bit challenging as a first text. Happily, there are other more introductory texts as well. Simply Scheme is a book designed to be read before SICP, easing beginners into the language as well as CS and programming in general. How to Design Programs is another text used in introductory college courses.

The quotation functionality of Lisp allow for extremely powerful, yet syntactically straightforward metaprogramming via macros. This is more powerful than the C preprocessor while being less involved than something like Template Haskell or F# quotations.

Using macros to properly decompose a problem domain teaches new developers good habits, improving composibility and reliability when tackling large programs. Scheme metaprogramming also serves as a gentle introduction to domain specific languages.

Unlike most languages, Scheme actually accords both functional programming and imperative programming roughly equal status. Many other languages like Python and Java are staunchly imperative while SML and Haskell are primarily functional; Scheme is a nice middle ground.

Additionally, since Scheme syntax is extremely flexible, it can easily be re-purposed for teaching non-deterministic and logic programming. There is no need to learn a new language like Prolog when the same ideas can easily be expressed with Scheme syntax.

This gives students a good perspective on different ways to think about and organize programs, which makes it much easier to move forward to other languages and technologies.

.NET offers rich functionality.

The Visual Studio IDE offers one of the best development environments. The Community Edition and Visual Studio Code can be used for free.

Can be designed visually with the Visual Studio designer for traditional Windows forms, WPF, or Web forms.

Lot's of tools and libraries available.

With Xamarin for Mobile (ios, android),
with .net core asp for server (linux, windows),
with .net core for desktop (windows, mac),
with mono for desktop (windows, linux),
with blazor for web client with webassembly.

However, it is not considered top for any of those categories, but it is top choice for Windows desktop with .net framework and top choice for Unity.

.net 5 will unify frameworks similar to JVM (just one).

Runs on Linux, Mac, and Windows.

Constant updates and bug fixes to many popular frameworks, as well as great first-party support from Microsoft. This can be a con as well in certain circumstances.

Being a C like language counts in favor for it as a general purpose programming language, given the ease of using existing skills to pick up this language easily.

There are other superior languages that could be used as a general purpose, such as: F#, Haskell, but the complexity of those languages, being functional, make them strange to the usual C Syntax.

C# is better than C whenever garbage collection, Objects, classes, data access, are needed. But C is going to be the choice when hardware access and performance are paramount.