MPG

Background:

1. Professional programmers carefully design the classes they need before any coding is done. With well-designed classes, programming is much easier and the program has fewer bugs. Object-oriented design consists of deciding what classes are needed, what data they will hold, and how they will behave. All these decisions are documented (written up) and then examined. If something doesn't look right, it is fixed before any programming is done.

2. The specifications of a class that models the fuel efficiency of a car could be:

Assignment:

1. Implement a Car class with the following properties.

   1. A Car keeps track of the starting odometer reading, ending odometer reading, and the number of gallons used between readings.

   2. The initial odometer reading is specified in the constructor.

   3. A method calculateMPG calculates and returns the miles per gallon for the car.

   4. A method fillUp simulates filling up the tank at a gas station: odometerReading is the current odometer reading and gallons is the number of gallons that filled the tank. Save these values in instance variables.

   5. With this information, miles per gallon can be calculated. calculateMPG will calculate the miles per gallon since the last time resetMPG was called.

2. Write a testing class with a main method that constructs a car and calls fillUp and calculateMPG a few times. Sample usage would be

   Car auto = new Car(15);
System.out.println(“New car odometer reading: ”);
auto.fillUp(150,8);
System.out.println(“Miles per gallon” + auto.calculateMPG());
System.out.println(“Miles per gallon” + auto.calculateMPG());
auto.resetMPG();
auto.fillUp(350, 10);
auto.fillUp(450, 20);
System.out.println(“Miles per gallon” + auto.calculateMPG());
auto.resetMPG();
auto.fillUp(603, 25.5);
System.out.println(“Miles per gallon” + auto.calculateMPG());

   Sample Output:

   New car odometer reading: 15
Miles per gallon: 16.875
Miles per gallon: 16.875
Miles per gallon: 10.0
Miles per gallon: 6.0