Computer.java

public class Computer{
  //fields
  private int gigsRam;
  private String os;

  //constructor
  public Computer( int g, String o ){
    gigsRam = g;
    os = o;
  }

  public Computer(){
    gigsRam = 2;
    os = "Ubuntu Linux";
  }

  //accessor
  public int getGigsRam(){
    return gigsRam;
  }

  public String getOS(){
    return os;
  }

  public double price(){
    double thePrice = gigsRam * 400;
    if( os.equals("Mac OSX") )
      thePrice *= 2;
    return thePrice;
  }

  public static void main(String[] args){
    Computer windows = new Computer(4, "Windows 10");
    Computer mac = new Computer(4, "Mac OSX");
    System.out.println( "The price of a " + windows.getOS() + " machine is " + windows.price() );
    System.out.println( "The price of a " + mac.getOS() + " machine is " + mac.price() );
  }
}