Picture a car dealership. There are many different types of vehicles for sale. The salespeople know every detail about every one. But the accountants inside only care that a vehicle is getting sold. Model this system:

1. The dealer sells Hatchbacks and Sedans
2. Every vehicle has a price
3. Hatchbacks have 5 doors and sedans have 4
4. Every vehicle has a trunk. A hatchback holds 30 cu ft, a sedan 20
5. Lastly, every vehicle can be started

Make two functions that take a Vehicle pointer as an argument. Call one Salesperson and the other Accountant.

The salesperson function:

1. Prints the type of car
2. Prints how many doors it has
3. Prints the trunk size
4. Starts the car

The Accountant function:

1. Prints the price

If you are looking at this in a panic, stop just looking at. You can see there is a Hatchback class and a Sedan class. They have a lot of similarities so they need a base class. Then just start putting things places. If you find you put the same thing in two classes, move it to the parent.