# 11.6. A more complicated example¶

Although the process of transforming functions into member functions is
mechanical, there are some oddities. For example, `after`

operates on
two `Time`

structures, not just one, and we can’t make both of them
implicit. Instead, we have to invoke the function on one of them and
pass the other as an argument.

Inside the function, we can refer to one of the them implicitly, but to access the instance variables of the other we continue to use dot notation.

```
bool Time::after (const Time& time2) const {
if (hour > time2.hour) return true;
if (hour < time2.hour) return false;
if (minute > time2.minute) return true;
if (minute < time2.minute) return false;
if (second > time2.second) return true;
return false;
}
```

To invoke this function:

```
if (doneTime.after (currentTime)) {
cout << "The bread will be done after it starts." << endl;
}
```

You can almost read the invocation like English: “If the done-time is after the current-time, then…”

The active code below is another practical example using the `after`

function.
Feel free to modify the time that school gets out, and the time that the track meet starts, if you wish!

- There is only one Time parameter.
- Incorrect! There are actually two Time parameters, one of them is implicit.
- The function operates on two Time objects.
- Correct! There are two Time objects - the implicit one and time2.
- The function is invoked on time2.
- Incorrect! The function is invoked on the implicit Time object.
- "hour" and "minute" refer to the hour and minute of the implicit Time object.
- Correct!

Q-2: Which is/are true about the `Time::after`

member function?

- One
- Incorrect! There is One implicit structure.
- Two
- Incorrect! Keep in mind there are 4 structures and 1 is implicit.
- Three
- Correct! There is One implicit structure, and three structures that need to be accessed with dot notation.
- Four
- Incorrect! We shouldn't need to use dot notation for all of them!

Q-3: In a function that operates on **four** structures, how many of them are accessed with dot notation?

Create the `Dog::is_older()`

function as it would be defined INSIDE of the `Dog`

structure definition. This function
checks if the current `Dog`

is older than another `Dog`

. The function is invoked on the current `Dog`

.