instructions.md

In this exercise you'll be playing around with a remote controlled car, which you've finally saved enough money for to buy.

Cars start with full (100%) batteries. Each time you drive the car using the remote control, it covers 20 meters and drains one percent of the battery.

The remote controlled car has a fancy LED display that shows two bits of information:

• The total distance it has driven, displayed as: "Driven <METERS> meters".
• The remaining battery charge, displayed as: "Battery at <PERCENTAGE>%".

If the battery is at 0%, you can't drive the car anymore and the battery display will show "Battery empty".

You have six tasks, each of which will work with remote controlled car instances.

1. Buy a brand-new remote controlled car

Implement the (static) RemoteControlCar.buy() method to return a brand-new remote controlled car instance:

RemoteControlCar car = RemoteControlCar.buy();

2. Display the distance driven

Implement the RemoteControlCar.distanceDisplay() method to return the distance as displayed on the LED display:

RemoteControlCar car = RemoteControlCar.buy();
car.distanceDisplay();
// => "Driven 0 meters"

3. Display the battery percentage

Implement the RemoteControlCar.batteryDisplay() method to return the distance as displayed on the LED display:

RemoteControlCar car = RemoteControlCar.buy();
car.batteryDisplay();
// => "Battery at 100%"

4. Update the number of meters driven when driving

Implement the RemoteControlCar.drive() method that updates the number of meters driven:

RemoteControlCar car = RemoteControlCar.buy();
car.drive();
car.drive();
car.distanceDisplay();
// => "Driven 40 meters"

5. Update the battery percentage when driving

Update the RemoteControlCar.drive() method to update the battery percentage:

RemoteControlCar car = RemoteControlCar.buy();
car.drive();
car.drive();
car.batteryDisplay();
// => "Battery at 98%"

6. Prevent driving when the battery is drained

Update the RemoteControlCar.drive() method to not increase the distance driven nor decrease the battery percentage when the battery is drained (at 0%):

RemoteControlCar car = RemoteControlCar.buy();

// Drain the battery
// ...

car.distanceDisplay();
// => "Driven 2000 meters"

car.batteryDisplay();
// => "Battery empty"