Thread: operator overloading >>

anyone have any idea how to ask the user to enter for each attributes without using cout in my operator overloading >> ? I still want to print out the Enter program name etc but not inside this function. According to my lecturer, its bad programming practice. Care to shed some light on how to do that?

my current code

Code:

istream &operator >> (istream& is, clsUniversityProgram &arg)
{
    // prompt to enter program name
    cout << endl << "Enter program name\t: ";
    is >> arg.programName;


    // prompt to enter program code
    cout << "Enter program code\t: ";
    is >> arg.programCode;


    // prompt to enter program fees
    cout << "Enter program fees\t: ";
    is >> arg.programFees;


    return is;
}

Generally, you would overload operator>> for input streams when you have some pre-determined input format such that you can say, parse input from a file. If you are going to prompt the user for input to populate the object part by part interactively, then overloading operator>> is not the right approach: just write another function.

Originally Posted by Alexius Lim

why is putting cout in input operator overloading a bad practice?

The convention is that operator>> when overloaded for std::istream is for reading formatted input. The input format is already known, so no prompting is necessary (or the prompting would have happened prior to the function call). Therefore, if there is output, it would likely just be for logging.

Originally Posted by Alexius Lim

i see... thanks. By the way, why is putting cout in input operator overloading a bad practice?

Because the purpose of overloading an operator is to act on its operand (or, in case of operator>>(), its operands). So a statement "s >> x" does something based on s and x, not something that affects some unrelated other object (like cout). If the operator>>() is a streaming operator, that means it reads a value to x from input stream s.

In your case, what would be the point of writing to cout if the supplied input stream is not cin?