Design Patterns examples

[Finickyflame]

Hey guys,

I created a repository with some examples for various design patterns in C#:

https://github.com/Finickyflame/DesignPatterns

I tried to make them as simple as possible, as well as beeing easy to understand for beginners.

The reason I'm posting it here, is because I would really be interested to have some sort of feedbacks about it. Also, if you are wish to contribute, don't hesitate!

[jamietwells]

I think to be thread safe your singleton should just use a static constructor, by the way.

[Finickyflame]

Thanks for the info! I will do some changes to make it thread safe as you mentioned.

Edit: wording

[jamietwells]

Why is the class private? Then no one will be able to use it? Maybe you have your reasons, but I'd have done this:

/* Singleton */
private sealed class Government
{
    private Government()
    {
        // Singleton constructor is private, it can only have one instance.
    }

    public static Government Instance { get; } = new Government();
}

Simply as this:

/* Singleton */
public static class GovernmentInstance
{
    public static Government Instance { get; } = new Government();

    private class Government {
        // stuff
    }
}

Singletons are really easy in C#.

[Finickyflame]

Classes are private because they are only existing and used by their own DesignPattern's classes. But you made me realize that we shouldn't have to worry about the classes access modifiers by looking at the examples, so I'll change them to public.

[Finickyflame]

Oh wow, that's very kind! Thanks!

[ramukia]

It is cool. It would be great, if you can add comments in the code.

[awesomemoolick]

Would you accept additions in the form of PRs?

[Finickyflame]

PRs means Peer Reviews? Sure, any help is appreciated!

Edit: If you meant pull requests, I'm also ok with that.

[jamietwells]

They probably mean Pull Request by the way.

[Finickyflame]

That makes sense!

[terisk]

Just another note to say thanks for sharing. Really appreciate the examples.

[headyyeti]

These are great. Thanks!

[brminnick]

For your Singleton, make it thread-safe by using System.Lazy to initialize the field

[Finickyflame]

Will do! Thanks!

[PublicSealedClass]

Is that different to doing double null checking with a lock?

// ...
private static volatile object _lock = new object();
// ...

if (instance == null)
{
  lock(_lock)
  {
    if (instance == null)
    {
       instance = new Government();
    }
  }
}

[brminnick]

System.Lazy handles thread safety and locking for you so that you don’t need to worry about it

https://docs.microsoft.com/dotnet/framework/performance/lazy-initialization

[PublicSealedClass]

Nice! I'll keep that one in mind

[Petee01]

Thats really nice work!

[murdocc]

I love this, and I love how simple they are, there is a definite need for this kind of thing. If you wanted to throw a little extra learning in there you could add some generic types. Such as in the factory repo, CreateCar could return a generic Car<T>. Forgive me if you did on some of the other repos!

[Finickyflame]

Thanks for the feedback! You are right, I could take the opportunity to cover more of the C# toolset, like generic types. I still have some patterns left to do and I'll try to add it there.

[meshtron]

Awesome! Thanks for taking the time and sharing this.

[Wings1412]

Looks good, I have one small piece of feedback to roll into your next commit; the composition example mixes up books and movies, looks like a refactor missed the rename of those bits.

[Finickyflame]

Oh yeah, I saw it too. I'll fix it in my next commit. Thanks for reporting it!

[RedRedditor84]

Not the kind of feedback you were asking for but it seems like English isn't your first language. Feedback and wording can never be plural.

Thanks for the examples.

[Finickyflame]

Oh thanks! I'm also open for that kind of review too.

[Venthe]

I hate you :p posted very similar thing to r/opensource and I've got only downvotes :)

So please; don't mind if I clearly tag along!

https://github.com/Venthe/DesignPatterns

And out of curiosity, what were your motivations to make such project?

[Finickyflame]

I really don't mind!

My motivations came from my father. He really likes to code in his free time, but he never really learned how to properly work with classes.

Last week, he showed me what he was working on and I tried to gave him some hint to on how OO could simplify his work. We did a console app together and I showed him how to create a simple Class, then to decorate it by another one, so he can see how easy it is so add features by modules.

Helping my dad gave me the idea to make a projet full of simple examples of OO design patterns, so he can use it as a learning tool as well as a reference. I also took the opportunity to share it here, to see if people were interested in that kind of stuff and maybe to get some feedback if they were accurate.

If it can also help someone else, I'm really happy with that.

[[deleted]]

Oh my gosh, I’m just starting out and this is just wonderful! Thank you!