Can a programmer write a definition for the class Car?

A good answer might be:

Of course! When you need a class that does something, and it has not already been defined, you can write the definition youself.

Here is the miles per gallon program. Both the class Car and the testing class MilesPerGallon are in the same source file, so you don't need to say import Car like the previous page did. To keep the program short, user interaction has been left out.

import java.io.* ;

class Car
{
  // instance variables


  // constructor


  // methods

}

class MilesPerGallon
{
  public static void main( String[] args ) 
  {
    Car car = new Car( 32456, 32810, 10.6 );
    System.out.println( "Miles per gallon is " + car.calculateMPG() );
  }
}

The source file must be named MilesPerGallon.java after the name of the class that contains main().

QUESTION 6:

Decide what variables should go in the data section. Look back to the for the class to see what you need.