Question

It allocates memory to the objects while creating to sane memory space.
but how to define the dynamic constructor.

plz explain with an example.

Thanks.

Answer 1

There is no dynamic constructor in C++. This is how to define a constructor for class A:

class A {
public:
    // Constructor
    A() { /* constructor code*/ }
};

This is how to allocate memory and construct the object:

A *a = new A();