1. Nelson Speaker Series Monica Lam, Stanford
Today's software is riddled with errors that can lead to catastrophic failures and vulnerabilities that compromise system integrity. This talk argues that we can greatly improve software reliability by capturing the "design rules" that govern a program and automatically preventing violations of such rules in the code. We have demonstrated the usefulness of this paradigm by developing concrete programming tools that can detect memory leaks statically, find root causes of complex errors, and translate application-specific design rules automatically into static and dynamic checkers.
Monica Lam, Stanford
Wed., Dec. 1, 7:00 pm in Galileo
ESA’s Ariane 5 rocket /4/96
The Ariane problem was due to a type error: a cast from a long integer to a short integer, which should only have been applied to a number less than 32768, was erroneously applied to a larger number that represented the "horizontal bias" of the flight. There was no code to handle the error, so it followed the usual fate of such exceptions and crashed the entire software, the on-board computers, and the mission.

2. Software Engineering:
CS 5 Today
Final project: a movie database (inspired by )
HW 14 (1 problem)
due Sunday, 12/5 at midnight
M/T sections
due Monday, 12/6 at midnight
Recitation -- 8am
W/Th sections
Human vs. Computer views of the same information…
Software Engineering:

3. Building from Hw 12: CS5App class
Choose an option from the following menu:
0 Display All Directors
1 Display All Films
2 Display Films by Title (or piece)
3 Display Films by Director
4 Display Films by Year
5 Display Films by Rating (G, PG, PG-13, R, NC-17, UC)
6 Display Films by Review (0 to 10)
7 Add a New Film
8 Save database to file
9 Read database from file
42 Quit
start with Hw14Pr1.zip

4. Methods class FilmDB class Film class Director class CS5App
public FilmDB(int capacity)
public boolean isFull()
public void addFilm(Film f)
public void displayAllFilms()
public void saveAllFilms()
public void displayFilmsByTitle(String titlepiece)
public void displayFilmsByYear(int year)
public void displayFilmsByRating(String rating)
public void displayFilmsByReview(double minreview)
public boolean checkForFilm(String fulltitle)
public int getCount() public int getCapacity()
Methods
class FilmDB
others are OK, too
private Film[] films;
private int count;
private int capacity;
class Film
public Film(String title, int year, String rating, double review, Director dir)
public String getTitle() public int getYear();
public String getRating() public double getReview()
public void display() public void save()
private int year;
private String title;
private String rating;
private double review;
private Director dir;
public DirectorDB(int capacity)
public void displayAllDirectors()
public void displayFilmsByDirector(String fname, String lname)
public Director findDirectorByName(String fname, String lname)
public void addDirector(Director dir)
public int getCount() public boolean isFull()
class DirectorDB
private Director[] dirs;
private int count;
private int capacity;
class Director
public Director(String fname, String lname, int capacity)
public String getFullName() public String getLName()
public FilmDB getFilmDB() public String getFName()
private String fname;
private String lname;
private FilmDB filmDB;
class CS5App
public static void main(String[] args)
static void printMenu() static void saveDB(String filePart)
static void readFilmEntry() static void readDB(String filePart)
static DirectorDB D;
static FilmDB F;

5. A film database: “Human” view
100 2
Lord of the Rings: Return of the King
Jackson
Peter
2003
PG-13
9.0
Gigli
Brest
Martin R
2.2
this is in the file twofilms.txt

6. A film database: “Human” view
capacity of database
100 2
Lord of the Rings: Return of the King
Jackson
Peter
2003
PG-13
9.0
Gigli
Brest
Martin R
2.2
count of Films that follow
title
L name
F name
use H.nl() to input Strings!
year
rating
review
the same sequence of data for each Film object
this is in the file twofilms.txt

7. D d f F A film database: “Computer” view objects: class DirectorDB
int count
Director[] dirs
Director[]
dirs[0]
dirs[1]
dirs
class Director d
String fname
FilmDB filmDB
FilmDB
filmDB
String lname
class Film
String rating f
String title
double review
Director
int year
Director dir
dir
class FilmDB F
int count
Film[]
films[0]
films[1]
Film[] films
films

8. relationships among data…
A film database: “Computer” view
class DirectorDB
int count
Director[] dirs
Director[]
dirs[0]
dirs[1]
dirs
relationships among data…
class Director
String fname
FilmDB filmDB
FilmDB
filmDB
String lname
class Film
String rating
String title
double review
Director
int year
Director dir
dir
class FilmDB
int count
Film[]
films[0]
films[1]
Film[] films
films

9. Never send a human to do a machine’s job
- Agent Smith, The Matrix

10. Human Computer translation
code in Hw14Pr1.zip
public static void saveDB(String fileNamePart) {
String fullFileName = "../" + fileNamePart + ".txt";
H.pl("Saving the database's contents to the file " + fullFileName);
H.outputToFile(fullFileName); // redirect the output to a file
H.pl(F.getCapacity()); // print the capacity (length of the array)
H.pl(F.getCount()); // print the count (# of actual films)
F.saveAllFilms(); // print all film data to the file
H.outputToConsole(); // redirect subsequent output to the console }
public static void readDB(String fileNamePart)
H.pl("Loading database contents from file " + fullFileName);
H.inputFromFile(fullFileName); // redirect input to come from the file
int capacity = H.ni(“Capacity:”); // reads in the capacity, an int
F = new FilmDB(capacity); // trashes old F and creates a new one
D = new DirectorDB(capacity); // trashes old D and creates a new one
int count = H.ni(“Count:”); // reads in the count, an int
for (int i = 0; i < count; i++) // for each film listed (up to count)...
readFilmEntry(); // read that film's entry into F
H.inputFromConsole(); // take subsequent input from the console
public static void readFilmEntry() // method to read 1 film entry

11. Saving the database public static void saveDB(String fileNamePart) {
code in Hw14Pr1.zip
public static void saveDB(String fileNamePart) {
String fullFileName = "../" + fileNamePart + ".txt";
H.pl("Saving to the file " + fullFileName);
H.outputToFile(fullFileName);
H.pl(F.getCapacity());
H.pl(F.getCount());
F.saveAllFilms();
H.outputToConsole(); }
100 2
LOTR: ROTK
Jackson
Peter
2003
PG-13
9.0
Gigli
Brest
Martin R
2.2
file

12. Reading the database public static void readDB(String fileNamePart) {
code in Hw14Pr1.zip
public static void readDB(String fileNamePart) {
String fullFileName = "../" + fileNamePart + ".txt";
H.pl("Loading DB from file " + fullFileName);
H.inputFromFile(fullFileName);
int capacity = H.ni(“Capacity:”);
F = new FilmDB(capacity);
D = new DirectorDB(capacity);
int count = H.ni(“Count:”);
for (int i = 0; i < count; i++)
readFilmEntry(); }
H.inputFromConsole();
100 2
LOTR: ROTK
Jackson
Peter
2003
PG-13
9.0
Gigli
Brest
Martin R
2.2
file

13. Constructors create an object F of type FilmDB
FilmDB data
Constructors
private int count;
private Film[] films;
create an object F of type FilmDB
private static FilmDB F; // outside of main
public static void main(String[] args) {
F = new FilmDB(100); // capacity == 100
in CS5App
public FilmDB(int capacity)
in FilmDB
same thing for the object D of type DirectorDB

14. Option 7: readFilmEntry
Be sure to find/create/add all of the objects needed…
checkForFilm
1) Prompt for the title
* Make sure that title is not yet in F
2) Prompt for the director: LName, FName
* Check to see if that director is already in D
Create and add the director to D, if necessary
3) Get the year, rating (G, PG), and review ( )
4) Create and add the film to F
5) Add the film to the director’s personal FilmDB
findDirectorByName

15. Constructors when adding a film… create a Director (if necessary)
Director data
Constructors
private FilmDB filmDB;
private String fname;
private String lname;
when adding a film… create a Director (if necessary)
in readFilmEntry in
CS5App
// prompt for the director’s last and first names
Director d = D.findDirectorByName(LN, FN);
if (d == null)
d = new Director(FN,LN,F.getCapacity());
public Director(String FN, String LN, int capacity)
in Director
create a Film
Film f = new Film(…)

16. null: the nonexistent object
a reference pointing to nothing!
Film f;
Film f = null;
equivalent statements
Film f
Any object (or array) can be set to null.
All objects (and arrays) are initially set to null.
Don’t try to call a method on a null reference!
The new operator creates a real (non-null) object.
Film f = new Film(…);
String title
int year
String rating …
Film f
methods & data

17. What is the count vs. the capacity of a FilmDB ?
The database(s)
FilmDB class
int count
Film[] films
Film[]
FilmDB
films[0]
films[1]
films[2]
films[3]
films[4]
films F
What is the count vs. the capacity of a FilmDB ?

18. Count vs. capacity public boolean isFull() { FilmDB class int count
Film[] films
Film
Film
Film
Film
Film
Film[]
FilmDB
films[0]
films[1]
films[2]
films[3]
films[4]
films F
in main
(option 7)
if (F.isFull())
H.pl(“Sorry! Buy me more memory!”);
public boolean isFull() {
in FilmDB

19. Getters / Setters public int getYear() { Film class String title
String rating
Director dir
int year
double review
Director
Film
dir f
else where
if (f.getYear() == 2006)
H.pl(“That movie hasn’t come out yet!”);
public int getYear() {
in Film

20. Retrieving information
All films of a certain year...
FilmDB class
Film[] films
int count
Film
Film
Film
Film[]
FilmDB
films
films[0]
films[1]
films[2]
films[3] F
public void displayFilmsByYear(int year) {
in FilmDB

21. Displaying/Saving a film…
Film class
String title
String rating
Director dir
int year
double review
Director
Film
dir f
else where
f.display(); // prints contents of f to the screen
f.save(); // prints contents of f to a file
public void save() // the formatting is crucial! {
in Film

22. A film database: “Human” view
100 2
Lord of the Rings: Return of the King
Jackson
Peter
2003
PG-13
9.0
Gigli
Brest
Martin R
2.2
this is in the file twofilms.txt

23. Quiz Recursive Movies (Hw14 ExCr)
For extra credit this week, use recursion for display, finding, & adding films and directors.
Use recursion to display all of the films that match the input year. Assume that x starts at 0.
public void displayFilmsByYear(int year, int x) { }
in the FilmDB class

24. Use recursion,if you like; assume that x starts at 0.
Quiz, p.2
Write the checkForFilm method that returns true if a film with the input title is already in the database, and false otherwise.
Use recursion,if you like; assume that x starts at 0.
public boolean checkForFilm(String title, int x) { }
in the FilmDB class

25. Methods class FilmDB class Film class Director class CS5App
public FilmDB(int capacity)
public boolean isFull()
public void addFilm(Film f)
public void displayAllFilms()
public void saveAllFilms()
public void displayFilmsByTitle(String titlepiece)
public void displayFilmsByYear(int year)
public void displayFilmsByRating(String rating)
public void displayFilmsByReview(double minreview)
public boolean checkForFilm(String fulltitle)
public int getCount() public int getCapacity()
Methods
class FilmDB
others are OK, too
private Film[] films;
private int count;
private int capacity;
class Film
public Film(String title, int year, String rating, double review, Director dir)
public String getTitle() public int getYear();
public String getRating() public double getReview()
public void display() public void save()
private int year;
private String title;
private String rating;
private double review;
private Director dir;
public DirectorDB(int capacity)
public void displayAllDirectors()
public void displayFilmsByDirector(String fname, String lname)
public Director findDirectorByName(String fname, String lname)
public void addDirector(Director dir)
public int getCount() public boolean isFull()
class DirectorDB
private Director[] dirs;
private int count;
private int capacity;
class Director
public Director(String fname, String lname, int capacity)
public String getFullName() public String getLName()
public FilmDB getFilmDB() public String getFName()
private String fname;
private String lname;
private FilmDB filmDB;
class CS5App
public static void main(String[] args)
static void printMenu() static void saveDB(String filePart)
static void readFilmEntry() static void readDB(String filePart)
static DirectorDB D;
static FilmDB F;

26. Methods class FilmDB class Film class Director class CS5App
public FilmDB(int capacity)
public boolean isFull()
public void addFilm(Film f)
public void displayAllFilms()
public void saveAllFilms()
public void displayFilmsByTitle(String titlepiece)
public void displayFilmsByYear(int year)
public void displayFilmsByRating(String rating)
public void displayFilmsByReview(double minreview)
public boolean checkForFilm(String fulltitle)
public int getCount() public int getCapacity()
Methods
class FilmDB
others are OK, too
private Film[] films;
private int count;
private int capacity;
class Film
public Film(String title, int year, String rating, double review, Director dir)
public String getTitle() public int getYear();
public String getRating() public double getReview()
public void display() public void save()
private int year;
private String title;
private String rating;
private double review;
private Director dir;
public DirectorDB(int capacity)
public void displayAllDirectors()
public void displayFilmsByDirector(String fname, String lname)
public Director findDirectorByName(String fname, String lname)
public void addDirector(Director dir)
public int getCount() public boolean isFull()
class DirectorDB
private Director[] dirs;
private int count;
private int capacity;
class Director
public Director(String fname, String lname, int capacity)
public String getFullName() public String getLName()
public FilmDB getFilmDB() public String getFName()
private String fname;
private String lname;
private FilmDB filmDB;
class CS5App
public static void main(String[] args)
static void printMenu() static void saveDB(String filePart)
static void readFilmEntry() static void readDB(String filePart)
static DirectorDB D;
static FilmDB F;

27. Adding to the Database(s)?
Film[] films
H. P.
S. W.
int count
Film
Film
Film
Film[]
films
films[0]
films[1]
films[2]
films[3]
films[4]
a Film to be added to our database…
String title (“LOTR: ROTK”)
int year (2003) …
Film f
methods & other data
Goal: output films in alphabetical order

28. Imposing order (Method 1) Add the new film at the end and call sort
From Justin to Kelly
The World of Batwoman
Da Hip Hop Witch
Gigli
films[0]
films[1]
films[2]
films[3]
films[4]
films[5]

29. Keeping order
(Method 2) Travel down the list, moving films over to find the right place for the new film
Lord of the Rings: ROTK
Shawshank Redemption
Seven Samurai
films[0]
films[1]
films[2]
films[3]
films[4]
films[5]

30. Keeping order
(2) Travel down the list, moving films over to find the right place for the new film
Lord of the Rings: ROTK
Shawshank Redemption
Godfather
Seven Samurai
films[0]
films[1]
films[2]
films[3]
films[4]
films[5]
start

31. Keeping order
(2) Travel down the list, moving films over to find the right place for the new film
compare
Lord of the Rings: ROTK
Shawshank Redemption
Godfather
Seven Samurai
films[0]
films[1]
films[2]
films[3]
films[4]
films[5]
start

32. Keeping order
(2) Travel down the list, moving films over to find the right place for the new film
Lord of the Rings: ROTK
Shawshank Redemption
Godfather
Seven Samurai
move over
films[0]
films[1]
films[2]
films[3]
films[4]
films[5]
next up

33. Keeping order
(2) Travel down the list, moving films over to find the right place for the new film
Lord of the Rings: ROTK
Shawshank Redemption
Godfather
compare
Seven Samurai
films[0]
films[1]
films[2]
films[3]
films[4]
films[5]
next up

34. Keeping order
(2) Travel down the list, moving films over to find the right place for the new film
Lord of the Rings: ROTK
Shawshank Redemption
Godfather
Seven Samurai
move over
films[0]
films[1]
films[2]
films[3]
films[4]
films[5]
next up

35. Keeping order
(2) Travel down the list, moving films over to find the right place for the new film
compare
Lord of the Rings: ROTK
Shawshank Redemption
Godfather
Seven Samurai
films[0]
films[1]
films[2]
films[3]
films[4]
films[5]
next up

36. Keeping order
(2) Travel down the list, moving films over to find the right place for the new film
Lord of the Rings: ROTK
Shawshank Redemption
Godfather
place
Seven Samurai
films[0]
films[1]
films[2]
films[3]
films[4]
films[5]
DONE!

37. Keeping order
(2) Travel down the list, moving films over to find the right place for the new film
or, equivalently...
Godfather
Seven Samurai
Lord of the Rings: ROTK
Shawshank Redemption
films[0]
films[1]
films[2]
films[3]
films[4]
films[5]

38. compareTo method String s = “startrek”;
s.compareTo(“starwars”) is < 0
s.compareTo(“starman”) is > 0
s.compareTo(“startrek”) is == 0
s.compareToIgnoreCase(…) 1 2 3 4 5 6 7
works the same way, but without considering upper/lower case distinctions

39. Keeping order
public void addFilm(Film f) (in FilmDB) {

40. Returns the index of the location of the substring.
Other notes: indexOf
When printing out all films that match a certain title, allow matches to any part of the title… use indexOf():
Returns the index of the location of the substring.
String s = “startrek”;
s.indexOf(“trek”) is 4
s.indexOf(“art”) is 2
s.indexOf(“wart”) is -1
-1 if the input is NOT a substring at all. Use this to decide which films to display…

41. Parting Wisdom
There is a difference between knowing the path and walking the path.
- Morpheus, The Matrix
Lab this week (optional):
You may (will) want to start early on this one…

42. Other notes
When finding a director, look through the list for matches and return null if not yet in the database...
public Director findDirByName(String LN, String FN) {
// loop through all of the directors
// if both names match, return that director object
// if nothing matches, return null }
When printing out all films that match a certain title, allow matches to any part of the title… use indexOf():
String s = “startrek”;
Negative if the input is NOT contained as a substring. Use this to determine which ones to display…
s.indexOf(“trek”) is 4
s.indexOf(“art”) is 2
s.indexOf(“wart”) is -1

43. A film database: class DirectorDB class Director class Film
int count
Director[] dirs
Director[]
dirs[0]
dirs[1]
dirs
class Director
String fname
FilmDB filmDB
FilmDB
filmDB
String lname
class Film
String rating
String title
double review
Director
int year
Director dir
dir
class FilmDB
int count
Film[]
films[0]
films[1]
Film[] films
films

44. Adding to the Database(s)
Film[] films
J. Park
Star Wars
Titanic
int count
Film
Film
Film
Film[]
films
films[0]
films[1]
films[2]
films[3]
films[4]
a brand new Film
String title (“LordOfTheRings”)
int year (2001) …
Film f
methods & other data
Goal: output films in alphabetical order

45. useful for checking if a string contains a particular substring!
Other hints
When finding a film name, allow the user to input a part of the name to look up -- use indexOf():
String s = “startrek”;
s.indexOf(“trek”) is 4
useful for checking if a string contains a particular substring!
s.indexOf(“art”) is 2
s.indexOf(“wart”) is -1

46. We can sort a list of 5 elements, how about one of 500,000 ?
CS 5 Today
The complexity of programs
or, the need for speed...
We can sort a list of 5 elements, how about one of 500,000 ? 80 10 42 7 73 L H
vs. problems we don’t know how to do at all! (Next week)
HW problem problems? Let me know!
HW 14 (1 problem)
due Sunday, 12/7 at midnight
M/T sections
due Monday, 12/8 at midnight
Recitation -- 8am
W/Th sections

47. Methods class FilmDB class Film class DirectorDB class Director
public FilmDB(int capacity)
public boolean isFull()
public int getCount()
public void addFilm(Film f)
public Film findFilmByTitle(String title)
public void displayAllFilms()
public void displayFilmsByTitle(String titlepiece)
public void displayFilmsByYear(int year)
public void displayFilmsByRating(String rating)
public void displayFilmsByReview(double minreview)
class Film
public Film(String title, int year, String rating, double review, Director dir)
public String getTitle()
public int getYear()
public String getRating()
public double getReview()
public void display()
class DirectorDB
public DirectorDB(int capacity)
public void displayAllDirectors()
public void displayFilmsByDirector(String fname, String lname)
public Director findDirectorByName(String fname, String lname)
public void addDirector(Director dir)
public int getCount()
public boolean isFull()
class Director
public Director(String fname, String lname, int capacity)
public String getFullName() public String getLName()
public FilmDB getFilmDB() public String getFName()

48. Methods class FilmDB class Film class DirectorDB class Director
public FilmDB(int capacity)
public boolean isFull()
public int getCount()
public void addFilm(Film f)
public boolean checkForFilm(String fulltitle)
public void displayAllFilms()
public void displayFilmsByTitle(String titlepiece)
public void displayFilmsByYear(int year)
public void displayFilmsByRating(String rating)
public void displayFilmsByReview(double minreview)
private Film[] films;
private int count;
private int capacity;
others are OK, too
class Film
public Film(String title, int year, String rating, double review, Director dir)
public String getTitle()
public int getYear()
public String getRating()
public double getReview()
public void display()
private int year;
private String title;
private String rating;
private double review;
private Director dir;
class DirectorDB
public DirectorDB(int capacity)
public void displayAllDirectors()
public void displayFilmsByDirector(String fname, String lname)
public Director findDirectorByName(String fname, String lname)
public void addDirector(Director dir)
public int getCount()
public boolean isFull()
private Director[] dirs;
private int count;
private int capacity;
class Director
public Director(String fname, String lname, int capacity)
public String getFullName() public String getLName()
public FilmDB getFilmDB() public String getFName()
private String fname;
private String lname;
private FilmDB filmDB;

49. Methods class FilmDB class Film class Director class CS5App
public FilmDB(int capacity)
public boolean isFull()
public int getCount()
public void addFilm(Film f)
public void displayAllFilms()
public void saveAllFilms()
public void displayFilmsByTitle(String titlepiece)
public void displayFilmsByYear(int year)
public void displayFilmsByRating(String rating)
public void displayFilmsByReview(double minreview)
public boolean checkForFilm(String fulltitle)
Methods
class FilmDB
others are OK, too
private Film[] films;
private int count;
private int capacity;
public Film(String title, int year, String rating, double review, Director dir)
public String getTitle()
public int getYear()
public String getRating()
public double getReview()
public void display()
public void save()
class Film
private int year;
private String title;
private String rating;
private double review;
private Director dir;
public DirectorDB(int capacity)
public void displayAllDirectors()
public void displayFilmsByDirector(String fname, String lname)
public Director findDirectorByName(String fname, String lname)
public void addDirector(Director dir)
public int getCount()
public boolean isFull()
class DirectorDB
private Director[] dirs;
private int count;
private int capacity;
class Director
public Director(String fname, String lname, int capacity)
public String getFullName() public String getLName()
public FilmDB getFilmDB() public String getFName()
private String fname;
private String lname;
private FilmDB filmDB;
class CS5App
public static void main(String[] args)
static void printMenu() static void saveDB(String filePart)
static void readFilmEntry() static void readDB(String filePart)
static DirectorDB D;
static FilmDB F;

50. Sorting recursively 80 10 42 7 73 A L U
void moveMinToLeft(double[] A, int L, int U) {
if (L == U) return;
if (A[L] > A[U]) // should we swap the last?
double x = A[L], y = A[U]; A[L] = y; A[U] = x; }
moveMinToLeft(A,L,U-1); // need to swap the rest…
void sort(double[] A, int L, int U)
if (L >= U) return;
moveMinToLeft(A,L,U); // sort the first element
sort(A,L+1,U); // sort the rest of them