C++ Primer Plus

Returning an Error Code

A more flexible approach than aborting is to use a function’s return value to indicate a problem. For example, the get(void) member of the ostream class ordinarily returns the ASCII code for the next input character, but it returns the special value EOF if it encounters the end-of-file. This approach doesn’t work for hmean(). Any numeric value could be a valid return value, so there’s no special value available to indicate a problem. In this kind of situation, you can use a pointer argument or a reference argument to get a value back to the calling program and use the function return value to indicate success or failure. The istream family of overloaded >> operators uses a variant of this technique. By informing the calling ...