Linked Questions

My sample program like below; public class Animal { public virtual string MakeSound() { return "General Sound"; } } public class Dog : Animal {...

i'm trying to understand the basics of polymorphism. I do understand why it could be useful to assign a superclass to a sub class or a sub to a super. what i don't understand quite well is the logic ...

As I've read the substitution of objects of a concrete type by instances of a subclass of that concrete type must preserve a program's correctness, a program's invariants. I'd like to know what ...

What does the expression "Turing Complete" mean? Can you give a simple explanation, without going into too many theoretical details?

I have a class Animal, and its subclass Dog. I often find myself coding the following lines: if (animal is Dog) { Dog dog = animal as Dog; dog.Name; ... } For the variable Animal ...

The word seems to get used in a number of contexts. The best I can figure is that they mean a variable that can't change. Isn't that what constants/finals (darn you Java!) are for?

What is the difference between syntax and semantics in programming languages (like C, C++)?

A lot of people seem to agree, that the Singleton pattern has a number of drawbacks and some even suggest avoiding the pattern entirely. There's an excellent discussion here. Please direct any ...

I need some resources that talk about how to design your software to be extensible, i.e. so that other people can write add-ons/plug-ins that adds functionality to it. What do you recommend? Any ...

My understanding of the Liskov substitution principle is that some property of the base class that is true or some implemented behaviour of the base class, should be true for the derived class as well....

I always thought functions and methods were the same, until I was learning Swift through the "Swift Programming Language" eBook. I found out that I cannot use greet("John", "Tuesday") to call a ...

For a unit test, I need to mock several dependencies. One of the dependencies is a class which implements an interface: public class DataAccessImpl implements DataAccess { ... } I need to set up ...

The Liskov Substitution Principle states that a subtype should be substitutable for that type (without altering the correctness of the program). Can someone please provide an example of this principle ...

When I design classes and have to choose between inheritance and composition, I usually use the rule of thumb: if the relationship is "is-a" - use inheritance, and if the relationship is "has-a" - use ...

In the comments of this answer it is stated that "checking whether the object has implemented the interface , rampant as it may be, is a bad thing" Below is what I believe is an example of this ...