Should an interface have properties?

Yes, An interface should define properties when it really in need. There is a IUser interface that has defined a property "Name" then you can use it without worry about if the object didn't implement the property.

Besides, cAN interface have properties?

Like a class, Interface can have methods, properties, events, and indexers as its members. But interfaces will contain only the declaration of the members. The implementation of interface's members will be given by class who implements the interface implicitly or explicitly.

Beside above, can we define properties in Interface C#? In C#, a class or a struct can implement one or more interfaces. In C#, an interface can be defined using the interface keyword. Interfaces can contain methods, properties, indexers, and events as members. An interface can only contain declarations but not implementations.

Also know, why do we need interface?

interface allows a class to behave like multiple types, which is not possible without multiple inheritance of class. It also ensures that you follow programming to interface than implementation pattern, which eventually adds lot of flexibility in your system.

Why interface Cannot have fields?

An interface can contain methods, properties, events or indexers. It cannot contain fields. Interfaces don't allow fields because they consist of a contract that is a list of methods, whose implementation is provided by a class. Properties are implemented as methods (get and set accessors), so they fit this model.

35 Related Question Answers Found

What is an interface?

In computing, an interface is a shared boundary across which two or more separate components of a computer system exchange information. The exchange can be between software, computer hardware, peripheral devices, humans, and combinations of these.

WHAT IS interface in OOP?

Interfaces in Object Oriented Programming Languages. An interface is a programming structure/syntax that allows the computer to enforce certain properties on an object (class). For example, say we have a car class and a scooter class and a truck class. Each of these three classes should have a start_engine() action.

Can we create object of interface?

NO we cant create an object of an Interface ,we use an Interface to hide the implementations from user. Interface contains only abstract methods and as abstract methods do not have a body (of implementation code) we can not create an object without constructor also .

Can we create instance of interface?

We can't create instance(interface can't be instantiated) of interface but we can make reference of it that refers to the Object of its implementing class. An interface can extends another interface or interfaces (more than one interface) . A class that implements interface must implements all the methods in interface.

What is an interface in C++?

An interface describes the behavior or capabilities of a C++ class without committing to a particular implementation of that class. Thus, if a subclass of an ABC needs to be instantiated, it has to implement each of the virtual functions, which means that it supports the interface declared by the ABC.

What is the benefit of using interface in C#?

By using interfaces, you can, for example, include behavior from multiple sources in a class. That capability is important in C# because the language doesn't support multiple inheritance of classes.

Why interface is used in C#?

An interface looks like a class, but has no implementation. -The reason interfaces only provide declarations is because they are inherited by classes and structs , which must provide an implementation for each interface member declared. Interfaces in C# are provided as a replacement of multiple inheritance.

What is difference between abstract class and interface?

Main difference is methods of a Java interface are implicitly abstract and cannot have implementations. A Java abstract class can have instance methods that implements a default behavior. Variables declared in a Java interface is by default final. An abstract class may contain non-final variables.

What is an interface in physics?

physics. Interface, surface separating two phases of matter, each of which may be solid, liquid, or gaseous. An interface is not a geometric surface but a thin layer that has properties differing from those of the bulk material on either side of the interface.

What is polymorphism in OOP?

In object-oriented programming, polymorphism refers to a programming language's ability to process objects differently depending on their data type or class. More specifically, it is the ability to redefine methods for derived classes.

What's the point of an interface Java?

What is the point of a Java interface? The point is to separate the API (what to do) from the implementation (how to do it). Interfaces are also necessary when using callbacks, since Java doesn't allow you to pass function references.

Can an interface extend a class?

Java interfaces cannot extend classes, which makes sense since classes contain implementation details that cannot be specified within an interface.. If you want to share code among all Vehicle instances, then you can use a (possibly abstract) class as a parent for any classes that need to implement that interface.

What is inheritance explain?

Inheritance is a mechanism in which one class acquires the property of another class. For example, a child inherits the traits of his/her parents. With inheritance, we can reuse the fields and methods of the existing class. Hence, inheritance facilitates Reusability and is an important concept of OOPs.

What is encapsulation in OOP?

Encapsulation is one of the fundamental concepts in object-oriented programming (OOP). It describes the idea of bundling data and methods that work on that data within one unit, e.g., a class in Java. This concept is also often used to hide the internal representation, or state, of an object from the outside.

Can an abstract class implement an interface?

In Java, an abstract class can implement an interface, and not provide implementations of all of the interface's methods. It is the responsibility of the first concrete class that has that abstract class as an ancestor to implement all of the methods in the interface.

Can abstract class have constructor?

Yes, an abstract class can have a constructor in Java. You can either explicitly provide a constructor to abstract class or if you don't, the compiler will add default constructor of no argument in abstract class. This is true for all classes and it also applies to an abstract class.

Can we create object of abstract class?

Because it's abstract and an object is concrete. No, designers did not provide a way. Because an abstract class is an incomplete class (incomplete in the sense it contains abstract methods without body and output) we cannot create an instance or object; the same way you say for an interface.