Whenever they are passed as parameters to a function, the io classes istream and ostream must be passed using a pass-by-reference parameter passing scheme.
select one:
a. false
b. true

b. TRUE

Explanation:

Whenever they are passed as parameters to a function, the IO classes istream and ostream must be passed using a pass-by-reference parameter passing scheme.

This is because , assuming a pass by value semantics would require us to copy the value of the istream or ostream object which would be meaningless. In fact these objects don't even have a copy constructor at all. So such objects are always passed by reference.

it can either be 2. or 4. : ) tell me if i'm wrong or right