The C++Course provides a general introduction to programming in C++. It is based on A.B. Downey's book, How to Think Like a Computer Scientist. Click here for details.

Yet Another Example

The original version of convertToSeconds looked like this:

double convertToSeconds (const Time& time) {
  int minutes = time.hour * 60 + time.minute;
  double seconds = minutes * 60 + time.second;
  return seconds;

It is straightforward to convert this to a member function:

double Time::convertToSeconds () const {
  int minutes = hour * 60 + minute;
  double seconds = minutes * 60 + second;
  return seconds;

The interesting thing here is that the implicit parameter should be declared const, since we don't modify it in this function. But it is not obvious where we should put information about a parameter that doesn't exist. The answer, as you can see in the example, is after the parameter list (which is empty in this case).

The print function in the previous section should also declare that the implicit parameter is const.

Last Update: 2006-12-10