cout/cin overload

Oh, and the cin being istream can be overloaded in the same fashion (of course, the class you're overloading for cannot be const in this case, and you must remove any formatting you define in the ostream - I've ignored this removal because it would complicate matters, and I'd probably get it wrong anyway :)

istream& operator>> (istream& s, WriteMe& write)
{
   s >> write.m_writethis;
   return s;
}

Of course in a real case, you'd have to put all sorts of error checking in there too.

you would use this exactly as you would a built in type:

WriteMe   bob;
bob.m_writethis = 77;
cout << bob;

...

WriteMe   bill;
cin >> bill;  //ignoring the formatting again.

The above code ( tested for cout )did not got compiled.
But when I changed the overload function to friend function it got magically compiled.
I dont know why I got problems and by friend function how it solved/ redirected the purpose.

Can you explain ?

I just wanted to make a technical point.

cin and cout are objects. It's not possible to overload them, and the phrase doesn't even mean anything. It's only possible to overload functions (of which operators like << are a special case).

when you employ Iainhere's solution (he correctly guessed what you meant), you are using a different(overloaded) operator<<, but the same cin and cout.

It's possible to over*ride* cin and cout by saying something silly like

float cin;

or

string cout;

after which operator<< doesn't work any more..

>>But when I changed the overload function to friend function it got magically compiled.

Could you post the code - I don't understand.  In the meantime, here's the code for a functioning example (I just tested it).

#include <iostream>
using namespace std;

class WriteMe{
public:
   double m_writethis;
};

ostream& operator<< (ostream&s, const WriteMe& write)
{
  return s << "your formatting here " << write.m_writethis;
}

int main(int, char**)

{
     WriteMe jeff;
     jeff.m_writethis = 33;
     cout << jeff;    
     return 0;
}

I think you forgot this question. I will ask Community Support to close it unless you finalize it within 7 days. Unless there is objection or further activity,  I will suggest to accept "glebspy, IanHere" comment(s) as an answer.

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======
Werner