Reading a class object with cin.

[gaurav#]

I have used member variables and operated on them with the help of member functions. Bu in one of the examples in C++ Primmer i found something like this:

Sales_item book;               \\book is an object of class Sales_item
cin>>book;
cout<<book;

How is it possible to read the object and output that after processing without using '.' operator and any member variable/function? I tried looking into the header "Sales_item.h" but didn't understand that.

[Elkvis]

You'll need to overload the >> operator for your class type. Something like this:

std::istream& operator>>(std::istream& is, Sales_item& item)
{
  is >> item.some_field;
  is >> item.some_other_field;

  return is;
}

And then do something similar with the << operator and std::ostream.

Of course this is a very oversimplified example. You need to check for errors at every step of the way.

[Salem]

operator overloading - cppreference.com
Scroll down to "Stream extraction and insertion"