Question

For this project you will be writing up a simple Clock program to keep track of time.

SimpleClock.java - contains your implementation of the SimpleClock class. You will need to provide the code for a constructor as well as the mutator methods set and tick and the accessor method toString. Look at the comments for each method to see how they should be implemented - the trickiest method is probably tick, which requires that you deal with the changing of minutes, hours and AM/PM in order to get it to work correctly.

/**
* SimpleClock.java
*
* A class that implements a simple clock.
*
* @author ENTER YOUR NAME HERE
* @version ENTER THE DATE HERE
*
*/
public class SimpleClock {

/* -------- Private member variables --------------------- */
private int hours;
private int minutes;
private int seconds;
private boolean morning;

/* -------- Constructor --------------------------------- */
/**
* The constructor should set the intial value of the clock to 12:00:00AM.
*/
public SimpleClock() {
// TODO - complete this constructor

}

/* --------- Instance methods ------------------------- */

/**
* Sets the time showing on the clock.
*
* @param hh
* - the hours to display
* @param mm
* - the minutes to display
* @param ss
* - the seconds to display
* @param morning
* - true for AM, false for PM
*/
public void set(int hh, int mm, int ss, boolean morning) {
// TODO - complete this procedure

}

/**
* Advances the clock by 1 second. Make sure when implementing this method
* that the seconds "roll over" correctly - 11:59:59AM should become
* 12:00:00PM for example.
*/
public void tick() {
// TODO - complete this procedure

}

/**
* Returns a string containing the current time formatted as a digital clock
* format. For example, midnight should return the string "12:00:00AM" while
* one in the morning would return the string "1:00:00AM" and one in the
* afternoon the string "1:00:00PM".
*
* @return - the current time formatted in AM/PM format
*/
@Override
public String toString() {
// TODO - complete this function

// TODO - the following line is only here to allow this program to
// compile. Replace it and remove this comment when you complete
// this method.
return "NOT IMPLEMENTED";
}

}

Answer 1

Here is the completed code for this problem. Comments are included, go through it, learn how things work and let me know if you have any doubts or if you need anything to change. If you are satisfied with the solution, please rate the answer. Thanks

Also included a Test class for testing. Ignore if you don’t need it.

// SimpleClock.java

public class SimpleClock {

      /* -------- Private member variables --------------------- */

      private int hours;

      private int minutes;

      private int seconds;

      private boolean morning;

      /* -------- Constructor --------------------------------- */

      /**

      * The constructor should set the intial value of the clock to 12:00:00AM.

      */

      public SimpleClock() {

            // using default values

            hours = 12;

            minutes = 0;

            seconds = 0;

            morning = true;

      }

      /* --------- Instance methods ------------------------- */

      /**

      * Sets the time showing on the clock.

      *

      * @param hh

      *            - the hours to display

      * @param mm

      *            - the minutes to display

      * @param ss

      *            - the seconds to display

      * @param morning

      *            - true for AM, false for PM

      */

      public void set(int hh, int mm, int ss, boolean morning) {

            // validating all fields before assigning

            if (hh < 1 || hh > 12) {

                  System.out.println("Invalid hour!");

            } else if (mm < 0 || mm > 59) {

                  System.out.println("Invalid minutes");

            } else if (ss < 0 || ss > 59) {

                  System.out.println("Invalid seconds");

            } else {

                  // all values are valid

                  hours = hh;

                  minutes = mm;

                  seconds = ss;

                  this.morning = morning;

            }

      }

      /**

      * Advances the clock by 1 second. Make sure when implementing this method

      * that the seconds "roll over" correctly - 11:59:59AM should become

      * 12:00:00PM for example.

      */

      public void tick() {

            // incrementing seconds

            seconds++;

            // checking if seconds go out of range

            if (seconds > 59) {

                  // resetting seconds, increasing minutes

                  seconds = 0;

                  minutes++;

            }

            // checking if minutes go out of range

            if (minutes > 59) {

                  // resetting minutes, incrementing hours

                  minutes = 0;

                  hours++;

                  // if hours is 12, switching the value of morning..ie if it is true,

                  // change to false, and vice versa

                  if (hours == 12) {

                        morning = !morning;

                  }

            }

            // if hours go out of range, resetting to 1

            if (hours > 12) {

                  hours = 1;

            }

      }

      /**

      * Returns a string containing the current time formatted as a digital clock

      * format. For example, midnight should return the string "12:00:00AM" while

      * one in the morning would return the string "1:00:00AM" and one in the

      * afternoon the string "1:00:00PM".

      *

      * @return - the current time formatted in AM/PM format

      */

      @Override

      public String toString() {

            // %02d specifies an integer value with max width of 2 spaces and padded

            // by 0. %2s specifies a string value of width 2

            // (morning ? "AM" : "PM") returns "AM" if morning is true, else "PM"

            return String.format("%02d:%02d:%02d%2s", hours, minutes, seconds,

                        (morning ? "AM" : "PM"));

      }

}

// Test.java

public class Test {

      public static void main(String[] args) {

            // creating a clock, testing set, toString and tick methods

            SimpleClock clock = new SimpleClock();

            System.out.println(clock);

            clock.set(11, 59, 59, true);

            System.out.println(clock);

            clock.tick();

            System.out.println(clock);

      }

}

/*OUTPUT*/

12:00:00AM

11:59:59AM

12:00:00PM