yes
Any class which has one or more abstract methods is called an abstract class. But in the normal class we can't have any abstract methods. We cannot create an object for the abstract classes. When we inherit the abstract class we should implement the abstract method which we inherit.
You can't put an abstract method (pure-virtual method) in a normal class because the normal class would become abstract itself. Only non-abstract classes can be physically instantiated as objects, and only if they fully implement all the abstract methods inherited from their base classes.
The term interface class does not exist in C#. If this is a term describing a class being an interface to other component (human, subsystems, etc), it is very application specific. The designer of that application should know the abstraction.However, C# does have another type called interface. An interface is NOT a class. An interface defines the intention of some behaviors that classes may be extended it and provides the implementation. The intention, is nothing but method signatures, which defines the return data type, the method name, and any method arguments and associated data type. The implementation is the code of the method. Interface is used for separating the concern of design and implementation.Abstract class is a class with abstract keyword. It can be just like a class without that keyword (then, why it is an abstract class?). But it may have some methods or properties defined as abstract. These abstract methods, like the method signatures of an interface, defines the intention.The subclasses of such an abstract class would need to implement those abstract methods (providing the code).There are more common, differences between interfaces and abstract classes, please see answer(s) of those related questions in C# category.
They are very different. An abstract class is a class that represents an abstract concept (google define "abstract" if you're unsure) such as 'Thoughts' or 'BankAccount'. When a class is defined as abstract it cannot be used (directly) to create an object. Abstract classes are used as super-classes so that all of their subclasses inherit all methods. Interfaces can be thought of as contracts with all of their implementing classes. They simply require all implementing classes to have methods with the same signature as that defined in the interface, but such methods can behave as appropriate. Hope that helps :)
Abstraction generally refers to abstract classes. An abstract class is one that cannot itself be instantiated, but can be derived from. Abstract classes are conceptual classes rather than concrete classes, and are intended to provide a common interface to the concrete classes derived from them. A class becomes abstract when it contains one or more pure-virtual methods, which must be implemented in the derived classes otherwise they become abstract classes themselves. A concrete class is one that provides a complete implementation for is abstract base classes, or inherits implementations from base classes other than those that originally declared the function to be pure-virtual. An example of an abstract class is Shape. All shapes can be drawn, therefore Shape will have a Draw() method. However, it cannot implement this method unless it knows what type of shape it actually is. Therefore the Draw() method should be declared pure-virtual, thus rendering the Shape class to be abstract. You can then derive concrete shapes from the Shape class, such as Circle and Square classes, which will each provide the actual implementation for the Draw() method. Since Square and Circle are types of Shape, you can create collections of Shape objects and call their Draw() methods without regard to their actual type. If the object is really a Square, then calling Shape.Draw() will actually invoke Square.Draw(). There is no need to determine the actual type of the shape because every shape has a common interface. This is really no different to overriding virtual methods in non-abstract classes. The main difference is that one would not be expected to instantiate a Shape (because it is abstract), other than through derivation, and the pure-virtual methods MUST be implemented by the derived classes, whereas normal virtual methods are simply expected to be overridden but it is not a requirement to do so unless you require an enhancement to the base class method. Abstract classes typically have few if any member variables and little or no implementation. Ultimately, the class exists purely to provide a common interface to all its derivatives, and only functionality and member variables that are common to all its derivatives should be placed within it. Even if the abstract class provides a complete implementation for all its pure-virtual methods, you cannot instantiate an abstract class -- it must be derived from -- and all pure-virtual methods must still be implemented in the derivatives, even if only to call the base class methods explicitly.
Below is the main difference between the 3 components:Concrete class - Provides implementation for all its methods & also for methods from extended abstract classes or implemented interfacesAbstract class - Does not provide implementation for one or more of its methodsInterface - Does not provide implementation for any of its methods
abstract class is a class label with abstract. It is just like a common class, with the following characterics: 1. Abstract class cannot be instantiate with an instance. 2. Abstract class may have abstract methods, while the normal class cannot have abstract methods. a virtual function in C# is a way to provide a default implementation for the class hierarchy. Both abstract class and common class (not sealed) can have virtual methods/ functions. Note that an abstract method (of an abstract class) is defining the intent, no codes (no default behavior), the implementation are left for the derived classes to do so. The virtual function if defined in an abstract class must define the implementation, the minimum is to do nothing: public abstract class Vehicle { public abstract int GetNumberOfTires(); public virtual void Move() { // default is doing nothing} } public class Car : Vehicle { public override int GetNumberOfTires() { return 4; } public override void Move() { throws new OutOfFuelExpection(); } }
final is a keyword.it can be used for three posibilities. they are ->we can assign the variable as final. to declaring the variable as final to avoid the reusability of a variable. now i display small program for this type. class A { final int i=10; a(int b) { i=b; System.out.println(i); } } public static void main(String args[]) { A x=new A(20); } } to execute this program .we have an error message.i.e.,the variable i can not be override. ->to use method have final keyword it can not be override.and also ->to use classes has final they can not be inhereted to sub classes.
Classes and Interfaces are the basis based on which the java programming universe revolves. Everything in Java is an object but an object is nothing but the runtime orientation of a class. In other words, an object is nothing but a class that is being executed.Whenever you write any java code, it implicitly means that you are writing classes or interfaces. Within those classes, as you know, are variables and methods (plus a few other things). How you declare your classes, methods, and variables dramatically affects your code's behaviorDeclaring Classes:A Class can be declared with the following statement:public class AnandsFirstclass {}Irrespective of the fact that this class does not have any code, this piece of code when saved in a file called AnandsFirstclass.java compiles just fine. Here public is an access modifier, class is the keyword that is used to specify that a class is being declared and AnandsFirstclass is the name of the class we are creating.There are many different types of classes that you can create. Some of which are:1. Final Classes - A class that cannot be inherited2. Normal Classes - The type of class that we declared a few lines back3. Abstract Classes - A class that is similar to a normal class but that does not provide full functional behaviour by itself. It has to be subclassed/inherited in order to be used.
ab for example ab-normal
Private virtual functions are useful when you expect a particular method to be overridden, but do not wish the override to be called from outside of the base class. That is, the base class implementation and its overrides remain private to the base class.Private virtual methods are particularly useful in implementing template method patterns, where certain algorithmic steps need to be deferred to subclasses, but where those steps need not be exposed to those subclasses. In many cases the private virtual methods will be declared pure-virtual, thus rendering the base class an abstract base class.
It depends on how the class is declared.If the class is a normal class - Then the compiler will complain. All the methods in an interface must be implemented by the class to successfully compile the classIf the class is declared as abstract - Then the compiler will ignore the fact that a few methods are not implemented