Question

Programming Assignment 1

Write a class called Clock. Your class should have 3 instance variables, one for the hour, one for the minute and one for the second. Your class should have the following methods:

• A default constructor that takes no parameters (make sure this constructor assigns values to the instance variables)
• A constructor that takes 3 parameters, one for each instance variable
• A mutator method called setHour which takes a single integer parameter. This method sets the value of the instance variable for the hour
• A mutator method called setMinute which takes a single integer parameter. This method sets the value of the instance variable for the minute
• A mutator method called setSecond which takes a single integer parameter. This method sets the value of the instance variable for the second
• An accessor method called getHour which takes no parameters and returns the value of the instance variable for the hour
• An accessor method called getMinute which takes no parameters and returns the value of the instance variable for the minute
• An accessor method called getSecond which takes no parameters and returns the value of the instance variable for the second
• A mutator method called tick. This will be similar to what we did in class, but this method will take an integer parameter. This parameter will specify how many ticks of the clock should take place. For example, tick(5) means to advance the clock 5 seconds. NOTE: The parameter can have a negative value, which means we tick backwards
• An accessor method called toString which returns a string representation of the time, in the following format: HH:MM:SS AM or HH:MM:SS PM

I am including a main program for you to use to test your class, and also a screenshot of what the expected output should be. (Note this main program doesn’t explicitly test all of your methods, but they should still be provided.)

General notes that apply to all programming assignments:

• Your class and all of its methods should be documented in accordance with the Javadoc Tool.  
• Every method of every class should ensure the integrity of its instance variables. For example, an instance variable that holds the number of days in a month must always be 28, 29, 30 or 31.
• You should always attempt to do your own work, but the truth is we often get outside help, intentionally or accidentally. If you get assistance from any person or resource, you must give credit to that person or resource. You won’t lose points. If you get outside help and don’t acknowledge it, you will receive a 0.
• If you write your program with another classmate, only one of you should submit the assignment, including a note indicating who you worked with. You will both get full credit. Again, I encourage students to do their own work, but teamwork is not always a bad thing. No more than two may collaborate on a program.

Here is the main program, just copy and paste:

public class clockTest

{

    /**

     * A main program to test the Clock class

     */

    public static void main (String[] args)

    {

        Clock myClock = new Clock(23, 59, 59);

        System.out.println ("The time is " + myClock.toString());

        myClock.tick(1);

        System.out.println ("After adding one second, the time is " +

                myClock.toString());

        myClock.tick(-1);

        System.out.println ("After subtracting one second, the time is " +

                myClock.toString());

        myClock.tick(86400);

        System.out.println ("After adding a full day, the time is " +

                myClock.toString());

        myClock.tick(43200);

        System.out.println ("After adding a half day, the time is " +

                myClock.toString());

        myClock.tick(60);

        System.out.println ("After adding a minute, the time is " +

                myClock.toString());

        myClock.tick(-3600);

        System.out.println ("After subtracting an hour, the time is " +

                myClock.toString());

       

    }

}

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

// Clock.java

public class Clock {

    // attributes

    private int hour;

    private int minute;

    private int second;

    // default constructor, initializes time to 12:00:00 AM or 0 hours 0 minutes

    // and 0 seconds

    public Clock() {

         hour = 0;

         minute = 0;

         second = 0;

    }

    // constructor taking values for each field

    public Clock(int hour, int minute, int second) {

         // validating and assigning values

         setHour(hour);

         setMinute(minute);

         setSecond(second);

    }

    // accessors and mutators for each field

    public int getHour() {

         return hour;

    }

    public void setHour(int hour) {

         // validating hour (in 24hr format) before assigning

         if (hour >= 0 && hour <= 23)

             this.hour = hour;

    }

    public int getMinute() {

         return minute;

    }

    public void setMinute(int minute) {

         if (minute >= 0 && minute <= 59)

             this.minute = minute;

    }

    public int getSecond() {

         return second;

    }

    public void setSecond(int second) {

         if (second >= 0 && second <= 59)

             this.second = second;

    }

    // method to advance or withdraw given number of seconds from the current

    // time

    public void tick(int seconds) {

         // checking if seconds is positive

         if (seconds > 0) {

             // looping for seconds number of times

             for (int i = 0; i < seconds; i++) {

                 // advancing second

                 this.second++;

                 // if second go out of range, wrapping from 0 and advancing

                 // minute

                 if (this.second > 59) {

                      this.second = 0;

                      this.minute++;

                 }

                 // if minute is out of range, advancing hour

                 if (this.minute > 59) {

                      this.minute = 0;

                      this.hour++;

                 }

                 // if hour is out of range, wrapping around from 0

                 if (this.hour > 23) {

                      this.hour = 0;

                 }

             }

         } else {

             // looping for -seconds number of times

             for (int i = 0; i < -seconds; i++) {

                 // decrmenting second

                 this.second--;

                 // wrapping around second, minute or hour if necessary. this

                 // time, checking for the lower bounds

                 if (this.second < 0) {

                      this.second = 59;

                      this.minute--;

                 }

                 if (this.minute < 0) {

                      this.minute = 59;

                      this.hour--;

                 }

                 if (this.hour < 0) {

                      this.hour = 23;

                 }

             }

         }

    }

    public String toString() {

         // initially assuming time is "AM"

         String amPM = "AM";

         // if hour field is 12 or above, setting amPM to "PM"

         if (hour >= 12) {

             amPM = "PM";

         }

         // taking hour value

         int h = hour;

         // if hour is 0, setting h to 12 (0 hour in 24 hr format is 12 hour in

         // 12 hr format)

         if (h == 0) {

             h = 12;

         }

         // otherwise if h exceeds 12, subtracting 12 from time to convert 24 hr

         // time into 12 hr time

         else if (h > 12) {

             h = h - 12;

         }

         //returning a String in HH:MM:SS AM/PM format

         return String.format("%02d:%02d:%02d %s", h, minute, second, amPM);

    }

}

/*OUTPUT*/

The time is 11:59:59 PM

After adding one second, the time is 12:00:00 AM

After subtracting one second, the time is 11:59:59 PM

After adding a full day, the time is 11:59:59 PM

After adding a half day, the time is 11:59:59 AM

After adding a minute, the time is 12:00:59 PM

After subtracting an hour, the time is 11:00:59 AM