I know that an interface is like a 100% pure abstract class. So, it can't have method implementation in it. But, I saw a strange code. Can anyone explain it? Code Snippet: interface Whoa { publ...

I'm trying to write a custom JsonConverter for cases where a person subclasses a list or collection, but then adds extra properties to the subclass (see here). The current implementation of JSON.NE...

I have a trait in Rust that offers a few default implementations for its functions. trait MyTrait { fn do_something(&self); fn say_hello(&self) { println!("Hello I am default")...

Java 8 introduced the concept of default implementation for interfaces? Isn't this violating Open Closed Principle, since based on the example on https://docs.oracle.com/javase/tutorial/java/IandI/...

I recently read about C# 8.0 having interface default implementations, so i went into my project and tried it out, but i was met with an error instead. Target runtime doesn't support default interf...

I have a trait MyTrait, and I want all trait objects &dyn MyTrait to be comparable to each other and to nothing else. I have that now based on How to test for equality between trait objects?. T...

Here's what I mean: // test.h class cls { public: template< typename T > void f( T t ); }; - // test.cpp template<> void cls::f( const char* ) { } - // main.cpp int main() { c...

I'd like to specify an Objective-C protocol with an optional routine. When the routine is not implemented by a class conforming to the protocol I'd like to use a default implementation in its place...

I was reading through this nice answer regarding the "Rule-of-five" and I've noticed something that I don't recall seeing before: class C { ... C& operator=(const C&) & = default; C...