A class is the definition of a type, from which objects can be instantiated. A method is a function of a class.
A class is the definition of a type, from which objects can be instantiated. A method is a function of a class.
Assuming class A has a method named getXXX() and class B is a sub class of class A. Now, if we write a method with the same name getXXX() in class B, with exactly the same signature as class A, it is called overriding a method. The method getXXX() in class A becomes the overridden method.
The method is only accessible to the class and friends of the class.
Yes - in Java, every class has this method, which is inherited from the Object class. Often, the inherited method does nothing particularly useful, but you can override it with your own implementation.
Method overloading is when you have multiple methods in a class that have the same name but a different signature. Method overriding is similar to method overloading, with a small difference. In overriding, a method in a parent class is overridden in the child class. The method in the child class will have the same signature as that of the parent class. Since the method in the child class has the same signature & name as the method of its parent class, it is termed as overriding. In situations where you may have to explicitly call the parent class method you can use the "super" keyword and for explicitly calling the current objects method you can use the "this" keyword.
Method overriding is similar to method overloading, with a small difference. In overriding, a method in a parent class is overridden in the child class. The method in the child class will have the same signature as that of the parent class. Since the method in the child class has the same signature & name as the method of its parent class, it is termed as overriding. In situations where you may have to explicitly call the parent class method you can use the "super" keyword and for explicitly calling the current objects method you can use the "this" keyword.
No. A method that is declared as private in a class is not inherited by any other class and hence if another class that extends this class declares a method with the same name and signature, it does not mean that this method is overridden. It is an entirely separate entity.
when overriding of a class or a method is necessary, they can be declared as abstract
No. Once a method is declared final in a class, no derivative of that class can override that method.
Inheriting a method means - a class is able to use a method that is declared in its parent class. Because of inheritance we need not re-declare the method in the child class again but still use it as it is. Overriding means re-declaring a method that is already available in the parent class in the child class to alter its features as per the requirement in the child class.
Use the scope resolution operator (::) to explicitly call the base class method. Note that the base class method must be protected or public in order for a derived class to access it. Private members are only accessible to the class itself and to friends of the class, regardless of whether the derivative uses public, protected or private inheritance. It is quite normal for a base class to provide a "default" implementation for a virtual method for which a derived class may override. Although the derived class will generally provide its own implementation of the method, it may also call the base class method either before, during or after performing its own implementation. The following shows minimal class declarations demonstrating a call to a protected base class method from a derived class override. class base { protected: // accessible to all instances of this class, its friends and its derivatives. virtual void method(){ /* do something */ } }; class derived : public base { public: // full-accessible outside of class. virtual void method(){ /* do something (or do nothing) */ base::method(); // call base class method. /* do something else (or do nothing) */ } };
Overriding relates to derived classes, where the derived class provides a new implementation for a method declared in the base class. The override is said to be a more-specialised implementation of the base class method, which is itself described as being a generic method. However, the derived class method can still call the base class method, if required.When the designer of a class can predict that their class will be derived from, they will normally provide virtual methods. These methods are expected to be overridden by the derived class. Overriding a non-virtual method can have side effects if the method is also overloaded. Overriding just one overloaded method will effectively hide all the other overloads in the base class, which may be undesirable.