public class ReceiptImproved {
  public static void main(String[] args) {
    final double TAX_RATE = 0.08;
    final double TIP_RATE = 0.15;
    double subtotal = 38 + 40 + 30;
    double tax = subtotal * TAX_RATE;
    double tip = subtotal * TIP_RATE;
    double total = subtotal + tax + tip;
    
    System.out.println("subtotal: " + subtotal);
    System.out.println("tax: " + tax);
    System.out.println("tip: " + tip);
    System.out.println("total: " + total);
  }
}