CS1110 About Prelim III: Tuesday, 14 April, 7:30–9:00PM, Ives Hall 305
Review session: Sunday, 12 April, 1:00–3:00, Phillips 101.
For this prelim, you need to know everything that you
needed to know for the first two prelims (see review
below). The handout for Prelim II (which you can get
from the course webpage) contains a list of topics as
well as a collection of concepts and definitions. These
deal with classes, subclasses, the class hierarchy, in-
heritance, overriding, casting, operator instanceof, ab-
stract classes, kinds of variables, methods and calls on
them, executing method calls, function equals, wrapper
classes, etc.
In any course such as this one, the material is cumula-
tive, and you need the old material to understand and
use the new material. Therefore, all material in the
course is fair game for the prelim.
Besides your normal studying, spend time, frequently,
practicing writing and testing Java code; that is the
only way to gain real fluency. Many of you restrict
your use of DrJava to what is required on the assig n-
ments and labs. That is a mistake; you are not required
to limit yourself to labs and assignments! For example,
if your answers to a sample prelim don’t match our
solutions, try typing in your (or our) solutions to
DrJava and seeing what happens.
Below, we give some more details on what can be on
prelim 3:
For loops. We may give you a problem that requires
you to write a loop (with initialization) that processes a
range of integers. You should be able to write a post-
condition, then write the loop header "for (int k ...)",
then write a loop invariant, and finally develop the
various parts of the loops and initialization.
While loops. We may give you a precondition, post-
condition, and a loop invariant, and you will have to
develop the loop, with initialization, from it. The grade
will depend on how well you deal with the four loopy
questions and the given invariant. The only variables
that should be used (outside of variables declared in the
repetend) are variables that are mentioned in the loop
invariant.
Arrays. Everything on Sects 8.1 and 8.2 of the class
text —these pages discuss the technical details for us-
ing arrays in Java and for reasoning about arrays, in-
cluding the range notation h..k (where h..h-1 is al-
lowed, and indicates the empty range). Two dimen-
sional arrays: You should know how to declare and use
rectangular arrays but not ragged arrays; see Sects.
9.1, 9.2.
Algorithms. You should know the following algo-
rithms. For example, if we ask "what is algorithm parti-
tion?"; you should be able to write the precondition and
postcondition (we won't give them to you), write down
the invariant, and then develop the loop with initializa-
tion. These algorithms are discussed in the text, on the
ProgramLive CD, and in lectures notes:
Algorithm Binary search (Sec. 8.5.3)
Algorithm Dutch national flag (done in lecture)
Algorithm Partition (PLive activity 8-5.5
class notes may be better)
Selection sort (Sec. 8.5.4)
Insertion sort
For selection sort and insertion sort, the repetend
should be written in English, stating what the repetend
does and not how it does it. Since you know that at
least one of these algorithms will be on the test, prac-
tice developing all of them. Answering this question
should take 5 minutes, because you know how to de-
velop them.
Classes String and Vector. We use these all the time.
You are expected to know the basic methods of these
classes: For class String: charAt(i), substring(i), sub-
string(i,j), length(). For Vector: add(ob), set(i, ob),
get(i), size(). If a question calls for other methods of
the classes, we will define them for you. You should
know that new Vector<C>(...) creates a Vector whose
elements are of class <C>.
Exception handling. Exception handling will not be
on prelim 3.
GUIS. We will not ask you questions about GUIs.
They may be on previous prelim 3’s but will not be on
this prelim 3.
Reading and writing files. You will not be asked to
memorize how to read and write files. We don’t re-
member either and look it up whenever we have to.