C# INTERVIEW QUESTIONS

When do you absolutely have to declare a class as abstract?

1. When the class itself is inherited from an abstract class, but not all base abstract methods have been overridden.

2. When at least one of the methods in the class is abstract.

What is an interface class?

Interfaces, like classes, define a set of properties, methods, and events. But unlike classes, interfaces do not provide implementation. They are implemented by classes, and defined as separate entities from classes.

Why can’t you specify the accessibility modifier for methods inside the interface?

They all must be public, and are therefore public by default.

What happens if you inherit multiple interfaces and they have conflicting method names?

It’s up to you to implement the method inside your own class, so implementation is left entirely up to you. This might cause a problem on a higher-level scale if similarly named methods from different interfaces expect different data, but as far as compiler cares you’re okay.To Do: Investigate.

What’s the difference between an interface and abstract class?

In an interface class, all methods are abstract - there is no implementation. In an abstract class some methods can be concrete. In an interface class, no accessibility modifiers are allowed. An abstract class may have accessibility modifiers.



What is the difference between a Struct and a Class?

Struts are value-type variables and are thus saved on the stack, additional overhead but faster retrieval. Another difference is that struts cannot inherit.

What’s the implicit name of the parameter that gets passed into the set method/property of a class?

Value. The data type of the value parameter is defined by whatever data type the property is declared as.

What does the keyword “virtual” declare for a method or property?

The method or property can be overridden.