when overloadind input/output stream operator, why return type??

[jaivrat]

When we overload the >> operator then why do we need to return the
istream by reference ? Why can't we do a void return?
(Quoting from a book )
e.g

istream & operator >>(istream & din, VectClass &v){
for( int i=0; i<= 3; i++)
din >> v;
return din;
}

 

[Mike Wahler]

When we overload the >> operator then why do we need to return the
istream by reference ?

You don't *have* to, but if you don't, you won't be
able to 'chain' calls such as:

cin >> a >> b >> c;

Why can't we do a void return?

You can if you like, but the function's use
will be more limited. Instead of the above,
you'd have to write:

cin >> a;
cin >> b;
cin >> c;

The choice is yours.

(Quoting from a book )
e.g

istream & operator >>(istream & din, VectClass &v){
for( int i=0; i<= 3; i++)
din >> v;
return din;
}

Which book are you reading that does not explain this?

-Mike

 

[puzzlecracker]

Which book are you reading that does not explain this?

comp.lang.c++

 

[Mike Wahler]

comp.lang.c++

That's not a book.

IMO one cannot learn a programming language by only
reading Usenet articles. You won't get far without
books.

-Mike

 

[jaivrat]

Thanks.