1. What
does the keyword virtual mean in the method definition?
The method can be over-ridden.
The method can be over-ridden.
2. Can you
declare the override method static while the original method is non-static?
No, you can’t, the signature of the virtual method must remain the same, only the keyword virtual is changed to keyword override.
No, you can’t, the signature of the virtual method must remain the same, only the keyword virtual is changed to keyword override.
3. Can you
override private virtual methods?
No, moreover, you cannot access private methods in inherited classes, have to be protected in the base class to allow any sort of access.
No, moreover, you cannot access private methods in inherited classes, have to be protected in the base class to allow any sort of access.
4. Can you
prevent your class from being inherited and becoming a base class for some
other classes?
Yes, that’s what keyword sealed in the class definition is for. The developer trying to derive from your class will get a message: cannot inherit from Sealed class WhateverBaseClassName. It’s the same concept as final class in Java.
Yes, that’s what keyword sealed in the class definition is for. The developer trying to derive from your class will get a message: cannot inherit from Sealed class WhateverBaseClassName. It’s the same concept as final class in Java.
5. Can you
allow class to be inherited, but prevent the method from being over-ridden?
Yes, just leave the class public and make the method sealed.
Yes, just leave the class public and make the method sealed.
6. What’s
an abstract class?
A class that cannot be instantiated. A concept in C++ known as pure virtual method. A class that must be inherited and have the methods over-ridden. Essentially, it’s a blueprint for a class without any implementation.
A class that cannot be instantiated. A concept in C++ known as pure virtual method. A class that must be inherited and have the methods over-ridden. Essentially, it’s a blueprint for a class without any implementation.
7. When do
you absolutely have to declare a class as abstract (as opposed to free-willed
educated choice or decision based on UML diagram)?
When at least one of the methods in the class is abstract. When the class itself is inherited from an abstract class, but not all base abstract methods have been over-ridden.
When at least one of the methods in the class is abstract. When the class itself is inherited from an abstract class, but not all base abstract methods have been over-ridden.
8. What’s
an interface class?
It’s an abstract class with public abstract methods all of which must be implemented in the inherited classes.
It’s an abstract class with public abstract methods all of which must be implemented in the inherited classes.
9. Why
can’t you specify the accessibility modifier for methods inside the interface?
They all must be public. Therefore, to prevent you from getting the false impression that you have any freedom of choice, you are not allowed to specify any accessibility, it’s public by default.
They all must be public. Therefore, to prevent you from getting the false impression that you have any freedom of choice, you are not allowed to specify any accessibility, it’s public by default.
10.Can you inherit multiple
interfaces?
Yes, why not.
Yes, why not.
