Constructors:

Constructors are similar to functions which has function identifier similar to class identifier. It gets executed when a object came into existence,i.e., when a object is created. There are variety of constructors. They are:

1.Default constructors
2.Parametrized constructors
3.Copy constructors
4.Overloading constructors

Default constructors:
        Default constructor are constructors which has no parameters. Default constructor assign default value as 0 to its public, private and protected data members.

Syntax:

class class_name

{

//class definitions

class_name()

{}

}

Example:

class book

{

int a,b;

public:

book()

{

}

};

int main()

{

book b;

}