Revise the class RoomCounter described in the previous exercise to use an assertion instead of an exception to prevent the number of people in the room from becoming negative.

Previous exercise

Suppose that you are going to create an object used to count the number of people in a room.

We know that the number of people in the room can never be negative. Create a 

RoomCounter class having three public methods:

• addPerson—adds one person to the room
• removePerson—removes one person from the room
• getCount—returns the number of people in the room

If removePerson would make the number of people less than zero, throw a NegativeCounterException.