What does a protected constructor do?

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.

When would you use a protected constructor?

A protected constructor can be used to make a class effectively abstract when none of its methods are pure-virtual.

  1. Technically, this applies only if ALL ctors are protected. …
  2. friend classes can also call the protected constructor (not just derived classes).

What happens if a constructor is declared 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.

What is the use of protected constructor in C#?

You can declare a constructor as private to prevent client code from directly instantiating an object. But then you can no longer subclass the class, because the derived class won’t have access to the constructor.

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What is correct about protected constructor?

What is true about protected constructor? Explanation: Protected access modifier means that constructor can be accessed by child classes of the parent class and classes in the same package. … Explanation: The class compiles successfully. But the object creation of that class gives a compilation error.

What is protected C#?

C# Protected Access Modifier

In c#, the protected modifier is used to specify that access is limited to the containing type or types derived from the containing class, so the type or member can only be accessed by code in the same class or in a derived class.

How do you call a protected constructor?

The only way to cause a protected constructor to be called is to derive from the class and have the derived class delegate to it or to have a static method create it or some other internal method.

What is protected function?

Protected : when a property or method visibility is set to protected members can only be access within the class itself and by inherited & inheriting classes. (Inherited:- a class can have all the properties and methods of another class).

When should I use protected in Java?

Use it when you need to do some internal stuff that is not exposed in public API but still needs to be overriden by subclasses. You need to use the protected access modifier, when you want the descendant class to see the fields / methods of the super class, BUT you do not want other classes to see these.

What is the use of protected keyword in Java?

2. The protected Keyword. While elements declared as private can be accessed only by the class in which they’re declared, the protected keyword allows access from sub-classes and members of the same package.

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Can we create protected constructor in C#?

The only way to cause a protected constructor to be called is to derive from the class and have the derived class delegate to it or to have a static method create it or some other internal method.

Can a constructor be protected in C#?

Instance constructor

Instance constructors can have public, private, protected, external, or internal modifiers. … Constructors can also be chained, i.e., you can invoke a base class constructor from a derived class constructor.

Can constructor be 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 is purpose of JTree Mcq?

The JTree class is used to display the tree structured data or hierarchical data. JTree is a complex component. It has a ‘root node’ at the top most which is a parent for all nodes in the tree. It inherits JComponent class.

Can a constructor be overloaded?

Yes! Java supports constructor overloading. In constructor loading, we create multiple constructors with the same name but with different parameters types or with different no of parameters.

What does this () mean in constructor chaining concept?

Constructor chaining is the process of calling one constructor from another constructor with respect to current object. … Within same class: It can be done using this() keyword for constructors in same class. From base class: by using super() keyword to call constructor from the base class.

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