The keyword “protects” the class from having its’ constructor called by external classes. However unlike the private keyword, protected will allow derived classes to access the class member.
Can constructor be protected?
Protecting a constructor prevents the users from creating the instance of the class, outside the package. During overriding, when a variable or method is protected, it can be overridden to other subclass using either a public or protected modifier only. Outer class and interface cannot be protected.
Why are constructors protected?
A protected constructor means that only derived members can construct instances of the class (and derived instances) using that constructor. This sounds a bit chicken-and-egg, but is sometimes useful when implementing class factories. … friend classes can also call the protected constructor (not just derived classes).
Can constructor be private in C?
5 Answers. Yes, a constructor can be private. And you can call it with member functions (static or non) or friend functions. For possible use cases, see the Factory Pattern, or the Named Constructor Idiom.
Are there any kind of protected constructors?
A protected constructor can be accessed by a class instance creation expression (that does not declare an anonymous class) or a method reference expression only from within the package in which it is defined.
Can a constructor be final?
No, a constructor can’t be made final. A final method cannot be overridden by any subclasses. … But, in inheritance sub class inherits the members of a super class except constructors. In other words, constructors cannot be inherited in Java therefore, there is no need to write final before constructors.
Can we make constructor static?
No, we cannot define a static constructor in Java, If we are trying to define a constructor with the static keyword a compile-time error will occur. … A constructor will be used to assign initial values for the instance variables. Both static and constructor are different and opposite to each other.
Can a class with private constructor be extended?
We can’t extend a class with a private constructor.
The constructor is private, so we can’t instantiate the class via the new keyword. Instead, we use the Vector#apply method.
Can we make constructor protected in C++?
Typically, constructors have public accessibility so that code outside the class definition or inheritance hierarchy can create objects of the class. But you can also declare a constructor as protected or private . Constructors may be declared as inline , explicit, friend or constexpr.
What happens if we declare constructor as protected?
protected: If you declare constructor as protected, any other child classes or classes within the same package can instantiate this class.
Can constructor be overridden?
Constructors are not normal methods and they cannot be “overridden”. Saying that a constructor can be overridden would imply that a superclass constructor would be visible and could be called to create an instance of a subclass.
What are types of constructor?
- Default Constructor.
- Parameterized Constructor.
- Copy Constructor.
- Static Constructor.
- Private Constructor.