I couldn't come to the final (and hence asked Richard to proctor it) because I was getting a hair cut. Then Richard came with the exams and I started grading. That was on Friday, at about 4pm (I remember it very well).

The most shocking thing about getting a buzz cut (I didn't go all the way) is that you suddenly realize your head is much smaller than you ever would have imagined. I've developed a sudden fear of ping-pong. Unfortunately, my ears, nose and glasses (I've started wearing glasses, I just felt I had to) stayed exactly the same size thus giving me a Mr. Potato Head look that I hope will one day become fashionable.

On the plus side, I find endless amusement rubbing my head with my hand. You would think I'd get bored doing that, but you would be mistaken. That's why it's taken me so long to post the grades; I'm typing with one hand. It did take me a long time (essentially, half of Friday and all of Saturday) but now grades have finally been posted and I am sure we all appreciate that.

I try to resist rubbing my head, but I don't have the willpower. I tried to cut down from two hands to one. I discover myself afraid that this could be like a gateway habit, a stepping-stone to worse addictions. And I try to soothe my anxiety by rubbing my head, which only makes things worse.

I truly hope you have enjoyed this class. I tried to put the best I had in it, and make it accurate and informative, while keeping it entertaining to the extent that one could have hoped for. I enjoyed working with each and every one of you, and I wish you the best of luck in your future endeavors.

Of all the minute papers there was one that I will remember forever. It was written on Thursday, before the exam, and had no signature nor name on it. In clear handwriting it went straight for the heart:

Dear Professor, today I love you more than tomorrow.

Have a great end of summer and my best of the best wishes to all of you.

Instructions for Students to complete CS evals through BEST:

1)  Go to http://www.indiana.edu/~best/
2)  Click on "Students" under "QuizSite"
3)  Click on Instructor and Course drop-down box
4)  Choose link to desired course evaluation
    All choices are preceeded by "csci"

        *LECTURE SECTIONS:
        Lecture sections are preceeded by an upper-case letter
        (ie: csci-A110)

        *LAB SECTIONS:
        Lab sections are preceeded by lower-case letter
        (ie: csci-a110)

5)  Choose "Do a Current Activity"
6)  Highlight name of instructor you wish to evaluate
7)  Click "Proceed" button
8)  Answer the 30 questions and click the "SUBMIT" button.
9)  **PLEASE REMIND STUDENTS TO CLICK THE SUBMIT BUTTON**
10) Repeat process for each additional lecture/lab instructor

But that means there will be no bonus extra problem either.

import java.util.*; 

class Nine {
  public static void main(String[] args) {
    Hashtable h = new Hashtable(); 
    h.put("a", "5");
    h.put("b", "6"); 
    String expr = "a + b"; 
    StringTokenizer st = new StringTokenizer(expr); 
    while (st.hasMoreTokens()) {
      String t = st.nextToken(); 
      if (h.get(t) != null) System.out.println(h.get(t)); 
      else System.out.println(t); 
    }
  }
}

import java.util.*; 

class Six { 
  public static void main(String[] args) {
    ConsoleReader in = new ConsoleReader(System.in); 
    while (true) {
      System.out.print("Six>"); 
      String line = in.readLine(); 
      if (line.equals("bye")) break; 
      StringTokenizer st = new StringTokenizer(line); 
      Vector v = new Vector(); 
      while (st.hasMoreTokens()) {
        String token = st.nextToken(); 
        v.addElement(token); 
      }
      System.out.println("Vector: " + v);

      boolean finished; 
      do { 
        finished = true; 
        System.out.println("Let's look at it, perhaps we're finished already..."); 
        finished = finished && eliminateRedundantParens(v);         
        System.out.println("parens says done? " + finished);

        // do the same with *'s
//      finished = finished && reduceStars(v);  
        finished = reduceStars(v) && finished;  
        System.out.println("stars says done? " + finished);

//      finished = finished && reducePluses(v);  
        finished = reducePluses(v) && finished;  
        System.out.println("pluses says done? " + finished);
      } while (! finished); 

      System.out.println("After processing: " + v);

    }
    System.out.println("Thanks, come back!");     
  } // main

  static boolean eliminateRedundantParens(Vector v) {
    boolean done = true; 
    for (int i = 1; i < v.size() - 1; i++) {
      if (isNumber((String) v.elementAt(i))     && 
          i >= 1 && v.elementAt(i-1).equals("(") &&
          v.elementAt(i+1).equals(")")
         ) {
        v.removeElementAt(i+1); 
        v.removeElementAt(i-1); 
        i -= 2; 
        done = false; 
        System.out.println("Ooops!... " + v); 
      } 
    }
    return done; 
  } // eliminateRedundantParens 

  static boolean isNumber(String str) {
    try {
      int num = Integer.parseInt(str); 
    } catch (Exception e) {
      return false; 
    }
    return true; 
  } // isNumber 

  static boolean reducePluses(Vector v) {

    boolean done = true; 

    for (int i = 1; i < v.size() - 1; i++) {

      if (v.elementAt(i).equals("+") && 
          isNumber((String)v.elementAt(i-1)) && 
          isNumber((String)v.elementAt(i+1)) &&

      ! ( (i-2) >= 0 && v.elementAt(i-2).equals("*") ||
          (i+2) < v.size() && v.elementAt(i+2).equals("*"))


         ) {
        int sum = Integer.parseInt((String)v.elementAt(i-1)) +
                  Integer.parseInt((String)v.elementAt(i+1));
        v.setElementAt(sum + "", i-1); 
        v.removeElementAt(i+1); 
        v.removeElementAt(i); 
        i -= 1; 
        done = false; 
      }
    }    
    System.out.println("Pluses: " + v); 

    return done;

  } // reducePluses

  static boolean reduceStars(Vector v) {

    boolean done = true; 

    for (int i = 1; i < v.size() - 1; i++) {

      if (v.elementAt(i).equals("*") && 
          isNumber((String)v.elementAt(i-1)) && 
          isNumber((String)v.elementAt(i+1))
         ) {
        int p = Integer.parseInt((String)v.elementAt(i-1)) *
                Integer.parseInt((String)v.elementAt(i+1));
        v.setElementAt(p + "", i-1); 
        v.removeElementAt(i+1); 
        v.removeElementAt(i); 
        i -= 1; 
        done = false; 
      }
    }    
    System.out.println("Stars: " + v); 

    return done;

  } // reducePluses


} // class Six

1. a volume of lecture notes, and
2. one of lab notes, exercises, exams, practice problems.

There will be a help session on Sunday August 4, in LH102, from 6:30-8:30pm.

import java.util.*; 
class Eval {
  public static void main(String[] args) {
    ConsoleReader c = new ConsoleReader(System.in);
    do { 
      System.out.print("Eval>"); 
      String line = c.readLine(); 
      StringTokenizer st = new StringTokenizer(line); 
      Vector v = new Vector();
      while (st.hasMoreTokens()) {
        v.addElement(st.nextToken());
      }
      for (int i = 0; i < v.size(); i++) 
        System.out.print(v.elementAt(i) + " "); 
      System.out.println(); 
    } while (true); 
  }
}

import java.applet.*;
import java.awt.*; 
import java.awt.event.*; 

public class One extends Applet implements MouseListener, 
                                           MouseMotionListener  {
  String where = "out"; 
  public void init() { 
    addMouseListener(this); addMouseMotionListener(this); 
  } 
  public void paint(Graphics g) { 
    if (where.equals("in")) { System.out.println("No smile."); }
    else { System.out.println("Broad smile."); }
  }

  public void mouseMoved(MouseEvent e) { System.out.println("A-ha!"); }
  public void mouseDragged(MouseEvent e) { }

  public void mouseClicked(MouseEvent e) { }
  public void mousePressed(MouseEvent e) { }
  public void mouseReleased(MouseEvent e) { }
  public void mouseExited(MouseEvent e) { 
    where = "out"; 
    repaint(); 
  }
  public void mouseEntered(MouseEvent e) { 
    where = "in";    
    repaint(); 
  }

}

Lecture Notes Twenty-Eight (for next Monday) provide a comprehensive review of inheritance (or, the Java class extension mechanism) concepts. The notes are long, and they may seem highly specialized, so start reading them now, and be patient: they give you the crux of the subject matter, leaving nothing out for later (or never.)

Although all of the presented examples are new, many concepts have already been covered, and therefore large portions of these notes can be used as a review so relax, and enjoy.

/*
     <applet code="Thirty.class" width=300 height=300>

     </applet>
 */

import java.applet.*; 
import java.awt.*; 
import java.awt.event.*; 

public class Thirty extends Applet implements MouseMotionListener, 
                                              MouseListener
 {

  int x0 = (int)(Math.random() * 200 + 50);
  int y0 = (int)(Math.random() * 200 + 50);
  int x1 = (int)(Math.random() * 200 + 50);
  int y1 = (int)(Math.random() * 200 + 50);

  public void paint(Graphics g) {

    for (float t = 0; t <= 1; t = t +   0.05f    ) {
      int x = (int)(x0 + t * (x1 - x0)); 
      int y = (int)(y0 + t * (y1 - y0)); 
      int r = 5;
      Color shade = new Color(0, 0.5f + t / 2, 0); 
      g.setColor(shade); 
      g.fillOval(x-r, y-r, 2 * r, 2 * r);
      g.setColor(Color.black); 
      g.drawOval(x-r, y-r, 2 * r, 2 * r); 

    }

  }

  public void init() {
    this.addMouseMotionListener(this);

    this.addMouseListener(this);

  }

  public void mouseMoved(MouseEvent e) { 
    int x = e.getX(), y = e.getY(); 

  }    

  public void mouseDragged(MouseEvent a) { 
    if (outside) { } else { 
      int x = a.getX(), y = a.getY(); 
      x1 = x; y1 = y; 
      this.repaint(); 
    }
  }    

  public void mousePressed (MouseEvent a) { 
    x0 = a.getX();
    y0 = a.getY(); 
    System.out.println("Changed x0, y0"); 
  }    

  boolean outside = true;

  public void mouseReleased(MouseEvent a) { }    
  public void mouseClicked (MouseEvent a) { }    
  public void mouseEntered (MouseEvent a) { 
    outside = false; 
    System.out.println("Mouse is now inside..."); 


  }    
  public void mouseExited  (MouseEvent a) { 
    outside = true; 
    System.out.println("Mouse is now outside..."); 

  }    


}

I will try to schedule one for next week, though.

1. Practice_Nine, and
2. Practice_Ten

What about x.horn if Horse x = new Unicorn(); ?

This, however, is a very good point, which has two parts.

1. First, as described today, it's okay to discard information (the horn) since this way you can keep Horses and Unicorns together (uniformly) in one array.

2. Second, since the horn is there, you can still access it, through casting, or if you point a Unicorn variable (read set of binoculars) to(wards) the Unicorn object.

We'll talk more about this aspect when we start using Vectors to store and retrieve objects.

Here's the code we wrote at the end of the class today:

/*
 <applet code="One.class" width=400 height=400>

 </applet>

 */ 

import java.applet.*; 
import java.awt.*;

public class One extends Applet {
  public void paint(Graphics g) {
    g.drawOval(30, 30, 100, 100); 
    g.drawOval(130, 130, 100, 200); 
    g.drawOval(230, 230, 150, 100); 
    g.drawOval(80, 80, 50, 50); 
  }
}

Notes for next week posted.

I won't be able to come to labs today, so you will be with Messrs. Li and Li (as you would, usually, on Mondays). I will return to labs next Thursday. If you need me in any way please let me know by e-mail or in class, or make an appointment, or come to any of my office hours.

Lab notes for today (including lab assignment) posted.

Notes updated a little bit for today and yesterday (some shifting happened).

First, the recursive bubble sort (with justification):

class One {
  public static void main(String[] args) {
    boolean done = true; 
    for (int i = 0; i < args.length - 1; i++) {
      if (Integer.parseInt(args[i]) > Integer.parseInt(args[i+1])) {
         done = false; 
         String temp = args[i]; 
         args[i] = args[i+1]; 
         args[i+1] = temp; 
      }
    } 
    if (done) {
      System.out.print("Here's the array sorted: "); 
      for (int i = 0; i < args.length; i++) 
        System.out.print(args[i] + " "); 
      System.out.println(); 
    } else { 
      One.main(args); 
    } 
  }
}

class Two {
  public static void main(String[] args) {
     String one = args[0], two = args[1]; 
     int max = Math.max(one.length(), two.length()); 
     System.out.println(max);  
     for (int i = 1, diff = max - one.length(); i <= diff; i++) {
       System.out.println("Adding zero no. " + i); 
       one = "0" + one; 
     }

     for (int i = 0; i < max - two.length(); i++) {
       two = "0" + two; 
     }

     System.out.println(" " + one + " + "); 
     System.out.println(" " + two + "   "); 
     for (int i = 0; i < max + 3; i++) System.out.print("-"); 
     System.out.println(); 
  }
}

All remaining homework assignments have been posted now.

Code used to produce sample output for third homework posted also, with question.

class One {
  public static void main(String[] args) {
    int[] a = One.generate(10, 0, 100);
    double avg = One.average(a); 
    One.show(a); 
    System.out.println("Average is: " + avg); 
  }

  static int[] generate(int size, int low, int hi) {
    int[] temp = new int[size]; 
    for (int i =0; i < size; i++) 
      temp[i] = One.value(low, hi); 
    return temp; 
  }

  static int value(int low, int hi) {
    return (int)(Math.random() * (hi - low) + low); 
  }

  static void show(int[] a) {
    for (int i = 0; i < a.length; i++) 
      System.out.print(a[i] + " ");
    System.out.println(); 
  } 

  static double average(int[] x) {
    double sum = 0;
    for (int i = 0; i < x.length; i++) 
      sum += x[i]; 
    return sum / x.length; 
  }

}

class Wednesday {
  public static void main(String[] args) {
    int[] a = { 5, 2, 3, 1, 6, 3, 4, 5, 1}; 
    Wednesday.show(a); 
    Wednesday.sort(a); 
    Wednesday.show(a); 
  }
  static void show(int[] b) {
    for (int i = 0; i < b.length; i++) {
      System.out.print(b[i] + " "); 
    }
    System.out.println(); 
  }
  static void sort(int[] b) {
    for (int i = 0; i < b.length; i++) {
      for (int j = i; j < b.length; j++) {
        if (b[j] < b[i]) {
          int temp = b[i]; 
          b[i] = b[j];
          b[j] = temp;
        }
      }
    }
  }
}

frilled.cs.indiana.edu%cat Arguments.java
class Arguments {
    public static void main(String[] args) {
	System.out.println("------------------------Case 1---"); 
        int   a = 3;  
	System.out.println("Before: " + a); 
	Arguments.fun(a); 
	System.out.println("After:  " + a); 
	System.out.println("------------------------Case 2---"); 
	int[] b = { 3, 1, 2, 4}; 
	System.out.println("Before: " + b[0]); 
	Arguments.fun(b); 
	System.out.println("After:  " + b[0]); 

    }
    static void fun(int n) {
	n += 1; 
    }
    static void fun(int[] n) {
	n[0] += 1; 
    }
}
[2]  - Done                 emacs Arguments.java
frilled.cs.indiana.edu%javac Arguments.java
frilled.cs.indiana.edu%java Arguments
------------------------Case 1---
Before: 3
After:  3
------------------------Case 2---
Before: 3
After:  4
frilled.cs.indiana.edu%

class Max {
  public static void main(String[] args) {
    ConsoleReader console = new ConsoleReader(System.in); 
    System.out.print("What size: "); 
    int size = console.readInt(); 
    int[] a = new int[size]; 
    for (int i = 0; i < size; i++) 
      a[i] = (int)(Math.random() * 50);

    System.out.print("Here's the array: "); 
    for (int i = 0; i < size; i++) 
      System.out.print(a[i] + " "); 

    int max = a[0]; 
    for (int i = 0; i < size; i++) 
      if (a[i] > max) 
        max = a[i]; 

    System.out.println("The max number is: " + max); 

  }
} 

import java.util.*;

class Backwards {
  public static void main(String[] args) {
    ConsoleReader console = new ConsoleReader(System.in); 
    System.out.print("Type a line: "); 
    String line = console.readLine(); 
    StringTokenizer stack = new StringTokenizer(line); 

    String result = ""; 

    while (stack.hasMoreTokens()) {
      String t = stack.nextToken(); 

      result = // result + " " + t; 

               t + " " + result; 
    }

    System.out.println(result); 
  }
} 

class Triangle {
  // Point a, b, c; 
   double ab, ac, bc; 
  // storing the squares of the sides here would solve the precision problem

  Triangle(Point a, Point b, Point c) { 
    // this.a = a; this.b = b; this.c = c; 
    ab = a.distanceTo(b); 
    ac = a.distanceTo(c); 
    bc = b.distanceTo(c); 
  } 

  boolean isRight() { 
    return (ab * ab == bc * bc + ac * ac) ||  
           // see lecture notes 6 and book chapter 5 for how we compare
           // floating-point numbers for equality (section 5.2.2, pp. 190-191) 
           (ac * ac == bc * bc + ab * ab) || 
           (bc * bc == ab * ab + ac * ac); 
  } 

  boolean isScalene() { 
    return (ab != ac && ab != bc && bc != ac); 
    // return ! this.isIsosceles(); 
  } 

  boolean isIsosceles() { 
    return (ab == ac || ab == bc || bc == ac); 
  } 

  boolean isEquilateral() { 
    // if (ab == bc && bc == ac) return true; else return false; 
    return (ab == bc && bc == ac); 
  } 

  public String toString() { 
    return "Triangle w/ sides: (" + ab + ", " + bc + ", " + ac + ")\n" +
          ab * ab + " " + bc * bc + " " + ac * ac ; 
  } 

  public static void main(String[] args) {
    System.out.println("Hello!"); 

    Triangle t1 = new Triangle( new Point(1, 0), 
                                new Point(), 
                                new Point(0, 3) ); 
 
    System.out.println(t1); 

    System.out.println("Is it a right triangle? Answer: " + t1.isRight()); 
    System.out.println("Is it a scalene triangle? Answer: " + 
                       t1.isScalene()); 
    System.out.println("Is it a isosceles triangle? Answer: " + 
                       t1.isIsosceles()); 
    System.out.println("Is it a equilateral triangle? Answer: " + 
                       t1.isEquilateral()); 

    System.out.println(2 + " == " + Math.sqrt(2) * Math.sqrt(2)); 

    java.awt.Rectangle r = new java.awt.Rectangle(2, 2, 10, 20); 

    System.out.println(r); 

  }
}

class Point { // from the Dilbert lecture 
    double x, y; 
    Point() {
	x = 0; 
	y = 0; 
    }
    Point(int initialX, int initialY) {
	x = initialX;
	y = initialY;
    }
    void report() {
	System.out.println("Point at: (" + x + ", " + y +")"); 
    } 
    double distanceTo (Point other) {
	double temp;
	temp = (x - other.x) * (x - other.x) +
	       (y - other.y) * (y - other.y); 

	return Math.sqrt(temp); 
    }
}

There's a help session tonight (Sun) in LH102 at 6:30pm.

Understanding

1. the Fraction Fraction, and
2. the Dilbert review notes

Grades for the midterm exam, minute paper statistics, posted.

Extra office hour tonight 8:30-9:30pm in LH016.

Notes for the rest of the week posted.

Here's an example of a problem that you might get on the practical exam:

Sample Practical Problem. Write a class called Triangle that can be used to represent a triangle. It should include the following methods that return boolean values indicating if the particular property holds:

1. isRight (a right triangle)
2. isScalene (no two sides are the same length)
3. isIsosceles (exactly two sides are the same length)
4. isEquilateral (all three sides are the same length)

Write a simple tester program that creates a few triangles and asks them about their type.

Homework Three posted.

Two more batches of exercises have been posted in QuizSite.

Exam on Friday (1:30pm in LH102) is multiple-choice, similar to the QuizSite exercises.

Lecture notes for today have been posted.

Warmups: Chapter Two Review Exercises
(http://www.cs.indiana.edu/classes/a201-dger/sum2002/notes/chapTwoReview.html)

Solutions for Chapter Two Warmups
(http://www.cs.indiana.edu/classes/a201-dger/sum2002/notes/chapTwoRevSols.html)

Programming Problems: Chapter Two Programming Exercises
(http://www.cs.indiana.edu/classes/a201-dger/sum2002/notes/chapTwoProbs.html)

Solutions for Chapter Two Programming Exercises
(http://www.cs.indiana.edu/classes/a201-dger/sum2002/notes/chTwoPSols.html)

Warmups: Chapter Three Review Exercises
(http://www.cs.indiana.edu/classes/a201-dger/sum2002/notes/w2.html)

Solutions for Chapter Three Warmups
(http://www.cs.indiana.edu/classes/a201-dger/sum2002/notes/w2Sol.html)

Programming Problems: Chapter Three Programming Exercises
(http://www.cs.indiana.edu/classes/a201-dger/sum2002/notes/set2.html)

Modeling with Diagrams.
(http://www.cs.indiana.edu/classes/a201-dger/sum2002/notes/rodS.html)

Solutions for Chapter Three Programming Exercises
(http://www.cs.indiana.edu/classes/a201-dger/sum2002/notes/set2Sol.html)

Warmups: Chapter Five Review Exercises
(http://www.cs.indiana.edu/classes/a201-dger/sum2002/notes/ifs.html)

Solutions for Chapter Five Warmups
(http://www.cs.indiana.edu/classes/a201-dger/sum2002/notes/ifsSol.html)

Programming Problems: Chapter Five Programming Exercises
(http://www.cs.indiana.edu/classes/a201-dger/sum2002/notes/pIfs.html)

Solutions for Chapter Five Programming Exercises
(http://www.cs.indiana.edu/classes/a201-dger/sum2002/notes/pIfsSol.html)

Please note that Lab Five this week is due in two stages.

An example of a plan of action involving decisions and decision-making.

I only need to initialize QuizSite now, with this semester's roster.

Here's the code we developed in class today:

class Two {
  public static void main(String[] args) {
    ConsoleReader console; 
    console = new ConsoleReader(System.in); 
    System.out.println("Hello, what's your name?"); 
    String name = console.readLine(); 
    System.out.println("Hello " + name + " enter a temperature in " + 
      " degrees Fahrenheit."); 
    double fahrenheit = console.readDouble(); 
    System.out.println( (fahrenheit - 32 ) * 5 / 9 ); 
  }
}

Please note a small change in my office hours time on Thursdays, below.

Today in class we will talk about

1. lecture notes three and four
2. a bit of lab notes two
3. indicate there's a homework assignment coming up
4. and that every lab (including the one tomorrow) also brings an assignment with it

Also we'll review and clarify the numbering used in Lab One for the tiles in the Rink.

1. Lecture Notes Two, and some more about
2. Lab Notes One.

   And with a big help of our friend the Penguin we will be looking at

3. Lecture Notes Three a little bit, as well.

   Our Penguin's name (by the way) is Pixel Pete.
   (The Aardman's penguin's name is Feathers, apparently).

Our office hours:

Instructor	Username	Days	Location	Time
Adrian German	dgerman	MTWF	LH201D	3-4pm
		Thursday(only)	LH201D	12:25-1:25pm
Richard Li	yli	TW	LH016 (basement, Lindley)	5:30-6:30pm
Barry Li	yinli	MR	LH016 (basement, Lindley)	2:30-3:30pm