Java How to Program (early objects), 9/e

8.2 Time Class Case Study

Our first example consists of two classes—Time1 (Fig. 8.1) and Time1Test (Fig. 8.2). Class Time1 represents the time of day. Class Time1Test is an application class in which the main method creates one object of class Time1 and invokes its methods. These classes must be declared in separate files because they’re both public classes. The output of this program appears in Fig. 8.2.

Time1 Class Declaration

Class Time1’s private int instance variables hour, minute and second (Fig. 8.1, lines 6–8) represent the time in universal-time format (24-hour clock format in which hours are in the range 0–23). Class Time1 contains public methods setTime (lines 12–25), toUniversalString (lines 28–31) and toString (lines 34–39). ...