Inheritance

Calling Base-Class Member Functions

A member function called without a parameter is called through the implicit parameter object of the derived class.
```
if (is_military())  /* clock uses military time */
   return (h + time_difference) % 24;
```
When the base class and the derived class have a member function with the same name, you must be more specific which function you want to call.
```
int TrvaelClock::get_hours() const
{
   int h = Clock::get_hours(); /* calls base-class function */
   . . .
}
```

The following call would die in an infinite recursion.

int TravelClock::get_hours() const
{
   int h = get_hours(); /* calls itself */
   . . . 
}