go to previous page   go to home page   go to next page

Answer:

The complete program is below. Copy it to a file and run it.


Complete Car


// File Car.java
//
class Car
{
  // instance variables
  double startMiles;   // Stating odometer reading
  double endMiles;     // Ending odometer reading
  double gallons;      // Gallons of gas used between the readings

  // constructor
  Car( double first, double last, double gals )
  {
    startMiles = first ;
    endMiles   = last ;
    gallons    = gals ;
  }

  // methods
  double calculateMPG()
  {
    return (endMiles - startMiles)/gallons ;
  }

}


// File MilesPerGallon.java
//
import java.util.Scanner ;

class MilesPerGallon
{
  public static void main( String[] args ) 
  {
    Scanner scan = new Scanner(System.in);

    double startMiles, endMiles, gallons;

    System.out.print("Enter first reading: " ); 
    startMiles = scan.nextDouble();

    System.out.print("Enter second reading: " ); 
    endMiles = scan.nextDouble();

    System.out.print("Enter gallons: " ); 
    gallons = scan.nextDouble();

    Car car = new Car( startMiles, endMiles, gallons  );

    System.out.println( "Miles per gallon is " + car.calculateMPG() );
  }
}


Each class is contained in a separate file. The calculateMPG() method returns a double value to the caller. Since it returns a value, there must be a return statement within its body that returns a value of the correct type.


QUESTION 10:

When you compile this program how many class files will there be?