PIC20A

Homework 4: Clock

Assignment

You are going to write a Clock class. The class has the following public constructor:

• public Clock(int hr, int min, int sec)

The class also has the following public members

• void setHr(int hr), void setMin(int min), void setSec(int sec)
• int getHr(), int getMin(), int getSec()
• increaseOneSec(): increse sec by one, it the sec becomes 60, increase min by one. if the min becomes 60, increase the hr by one. If the hr exceed 13, set it to 1.
• paint(Graphics g)

There should be no other public members.
The clock is not a real clock, i.e., it doesn't show you the real time. It doesn't move at all. Your clock is NOT necessary similar to mine. You can have a more complicated design.

How to calculate Angles

    private double getSecAngle() {
        return (6*sec)*2*Math.PI/360;
    }
    
     private double getMinAngle() {
        return (6*min)*2*Math.PI/360;
    }
    
    private double getHrAngle() {
        return ((30*hr) + (30* (6*min)/360)) * 2 * Math.PI/360;
    }

Test program

Notice that you don't have to set the title.

import javax.swing.*;

public class Test1 {
   public static void main(String[] args) {
       final Clock clock = new Clock(9, 25, 43);
       clock.setTitle("Clock 09:25:43");
       clock.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
       clock.setSize(400,400);
       clock.setVisible(true);
   }
}

import javax.swing.*;

public class Test2 {
   public static void main(String[] args) {
       final Clock clock = new Clock(2, 47, 22);
       clock.setTitle("Clock 02:47:22");
       clock.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
       clock.setSize(400,400);
       clock.setVisible(true);
   }
}

A real clock

import javax.swing.*;
import java.util.*;

public class RealClock {    
    public static void main(String[] args) {
       GregorianCalendar current = new GregorianCalendar();
       int hr = current.get(Calendar.HOUR);
       int min = current.get(Calendar.MINUTE);
       int sec = current.get(Calendar.SECOND);
       final Clock clock = new Clock(hr, min, sec);
       clock.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
       clock.setSize(400,400);
       clock.setVisible(true);
       new Thread(new Runnable() {
           public  void run() {              
               try {
                   while(true) {
                     clock.increaseOneSec();
                     Thread.sleep(1000);
                     clock.repaint();
                   }
               } catch(Exception e) {
               }
           }
       }).start();
       
    }
}

What to submit

Remark

• All source code submitted must contain the following information at the beginning of each file:
  • Your full name
  • Your student ID number
  • Your PIC login ID
  • Your e-mail address
  • Your discussion section number and TA's name
  • The assignment number and description
  • Honesty pledge
  Properly formatted, this information should appear as follows:(Please change the Name, Student ID, PIC ID, E-mail, Discussion

  /** Name:        Charles Li 
    * Student ID : 000 000 000   
    * PIC ID:      ccli 
    * E-mail:      ccli@math.ucla.edu 
    * Discussion:	 1A, Baber
    * Assignment:	 hw1 
    * 
    * I, Charles Li, pledge that this is my own independent work, which  
    * conforms to the guidelines of academic honesty as described in the course  
    * syllabus.  
    * 
    */
  

• If you develop your program on your home computer, make sure it compiles and runs on the lab machines before you turn it in.
• Please use consistent and neat indenting in all your programs.
• Please comment your program.

Solution

Clock.java