COS 126 Exam 2 Information, Fall 2009

Q+A.

There will be a Q+A Wednesday night, December 16, 8:00-10:00pm, Room CS 105.

The precept before the exam will be devoted to Q+A and review.

Rules: Written exam.

50 minutes, during last lecture time slot before reading period.
P01C and P02 will take the written exam in McCosh 50.
All other precepts will take the written exam in McCosh 10, our regular lecture hall. (P01, P01A, P01B, P03, P04, P04A, P04B)
Closed book, closed note.
You may bring one 8.5-by-11 sheet (two sides) with notes in your own handwriting to the exam.
No calculators (or computers!)

Rules: Programming exam.

50 minutes, during last precept time slot before reading period.
P04A and P04B will take the programming exam in Friend 004.
All other precepts will take the programming exam in their regular precept rooms (except for individuals who have made special arrangements).
Open book, open note, open computer --- yes, including the booksite!
Make sure that your laptop is charged (in case there aren't enough outlets in your precept room). If you don't have a working laptop, tell your preceptor.
For Part 1, set up an empty directory on your laptop that includes a copy of StdIn.java, StdOut.java, and In.java.
For Part 2, set up an empty directory on your laptop that includes the files for Part 1 and a copy of ST.java.

Material covered.

The exam will cover all material in the course, but with an emphasis on the second half of the course:

Introduction to Programming in Java, Sections 3.1-3.3, 3.5(booksite), 4.2-4.4.
Introduction to Programming in Java, Booksite 7.2-7.7
On-line Chapters 7 and 6 (links on Lecture page).
Booksite 5.2, 5.3 TOY (but not TOY programming).
Lecture notes 12-22.
Programming assignments 5-8.

The written part of the exam (in lecture) covers all of the above. It will be multiple-choice or short answer questions on the important material. The best way to prepare for this part of the exam is to read the book and to study the lecture notes.

The second part of the exam in precept is strictly about programming. You will be asked to write a program from scratch (a mini programming assignment). Given the time limitation, this program will not be conceptually difficult, just a test of your ability to write a program that solves a simple problem. The best way to prepare for this part of the exam is to work a few of the easy exercises in the book and on the booksite that call for writing small programs.

List of topics.

This list is a summary of the main topics on the exam, for your use as a checklist when studying. Do you understand the basic ideas behind each of these topics? Do you know the names and contributions of the major players? If not, reread the appropriate sections in the book and lecture slides.

Using data types
- declaring variables
- invoking constructors
- invoking methods
- reference types vs. primitive types
Creating data types
- instance variables
- constructors
- instance methods
Designing data types
- encapsulation (public/private)
- modular programming
- immutability
Sorting
- Insertion sort
- Mergesort
Data structures
- linked lists
- binary trees
- stacks and queues
- symbol tables
- which data structure is appropriate for which application
Theory of computing
- regular expressions (the 5 basic ops, don't need extra Java add-ons)
- DFAs (tracing and understanding, but not designing)
- Turing machines (tracing and understanding, but not designing)
- duality, universality, Church-Turing thesis, computability, halting problem
- Intractability (P, NP, NP-complete, P = NP question, extended Church-Turing thesis, reduction)
Combinational circuits
- Boolean logic
- AND, OR, NOT gates
- sum-of-products
Designing a CPU
- Building blocks
- Organization
- Layers of Abstraction
APIs.
You should be familiar with the following static methods (the ones we've encountered frequently in the lectures and assignments). If we want you to use some other library function, we'll remind you how it works.
```
Math.sqrt()
Math.abs()
Math.sin()
Math.cos()
Math.exp()
Math.log()
Math.random()
Math.E
Math.PI

System.out.println()
System.out.print()

Integer.parseInt()
Double.parseDouble()
Double.POSITIVE_INFINITY

StdIn.readInt()
StdIn.readDouble()
StdIn.readString()
StdIn.isEmpty()

StdDraw.line()
StdDraw.point()
StdDraw.circle()
StdDraw.setXscale()
StdDraw.setYscale()
StdDraw.clear()
StdDraw.show()
StdDraw.picture() 
StdDraw.filledPolygon()
```
You should also be familiar with the following data types and instance methods:
```
String data type:  charAt(), substring(), matches(), indexOf(), length()

In data type to read from files:  isEmpty(), readAll(), readLine(), 
readChar(), readInt(), readDouble(), readString()
```
Old Exams.

A good way to practice for the EXAM is to solve problems from old exams.
Warning 1: Some old exams include questions on topics that we have not covered this semester, for example sequential circuit timing diagrams, percolation, Quicksort.
Warning 2: Studying questions that ask you to write code is worthwhile, but bear in mind that some of the old exams were two hours, closed book, no computers. When looking at an old exam, check the cover sheet to see if it was a 50 minute exam or a 2 hour exam. This term, the written exam will not have questions that ask you to write a significant amount of code. The purpose of the programming exam is to test your ability to write code.