Change thePassenger class fromHomework 4-1, to anabstract class and add the following to it:

Implement theEater Interface.

Passenger // the class becomes anabstract class

• caloriesConsumed: int // this field is initialized to zero and will always increase
• caloriesAccumulator: int // this field is initialized to zero and is an accumulator

// that is reset whenmetabolizeAccumulatedCalories()

// (see below)

• getCaloriesConsumed() : int
• setCaloriesConsumed(int) : void
• getCaloriesAccumulator() : int
• setCaloriesAccumulator(int) : void
• metabolizeAccumulatedCalories() : double // anabstract method that returns adouble

// representing the amount of weight gained.

// Classes that inherit from Passenger will have to implement this method.

// Weight gain is calculated based on the number of accumulated calories

// represented bycaloriesAccumulator.

// Every Passenger uses a different formula for weight gain.

// In addition to returning the amount of weight gained, this method will update

// the Passenger's weight and zero outcaloriesAccumulator.

Change thePerson class fromHomework 4-2, to anabstract class.