What is a default constructor give one example?

In computer programming languages, the term default constructor can refer to a constructor that is automatically generated by the compiler in the absence of any programmer-defined constructors (e.g. in Java), and is usually a nullary constructor.

Copy Constructors is a type of constructor which is used to create a copy of an already existing object of a class type. It is usually of the form X (X&), where X is the class name. The compiler provides a default Copy Constructor to all the classes .

The default constructor initializes instance variables with default values . For example, the int variable will be initialized to 0. Constructor types: No-Arg Constructor – a constructor that does not accept any arguments.

A default constructor is a constructor that either has no parameters, or if it has parameters, all the parameters have default values . If no user-defined constructor exists for a class A and one is needed, the compiler implicitly declares a default parameterless constructor A::A() .