calculator.java

Java the UML Way 书中所有源码

/*
 * Calculator.java   E.L. 2001-08-10
 *
 */

class Calculator {
  private double number1;
  private double number2;

  public Calculator(double initNumber1, double initNumber2) {
    number1 = initNumber1;
    number2 = initNumber2;
  }

  public double getNumber1() {
    return number1;
  }

  public double getNumber2() {
    return number2;
  }

  public void setNumbers(double newNumber1, double newNumber2) {
    number1 = newNumber1;
    number2 = newNumber2;
  }

  public double calculateSum() {
    return number1 + number2;
  }

  public double calculateDifference() {
    return number1 - number2;
  }

  public double calculateProduct() {
    return number1 * number2;
  }

  public double calculateQuotient() {

    /* Division by zero gives special results:
     * Both numerator and denominator are 0: Result: Double.NaN ("not-a-number")
     * Only denominator is 0: Result: Double.NEGATIVE_INFINITY or
     *                          Double.POSITIVE_INFINITY.
     * Printing these values gives "NaN" and "Infinity".
     */
    return number1 / number2;
  }
}