Sample Questions for Quiz 2
CSCI 1902, Spring 2008

This is a set of sample questions for Quiz 2. It is intended to give
you a sense of what type of questions to expect on the exam; in
particular, it illustrates the different "levels of knowledge" of
exam questions.  

There are several things this set of questions is *not*.
(1) It is not a comprehensive list of the topics that may be covered.
    The best source for that is the lecture notes.
(2) It is not a sample quiz: the set of questions below would take
    longer than 25 minutes to complete
(3) It is not (syntactically speaking) an example of a successful
    "Quiz Question Proposal"; it contains more questions than
    necessary and no answers.

==============================
== KNOWLEDGE
==============================

Name three methods in the ADT List class.

--------------------

Write a Java statement to declare a variable whose value is a List of
Customer objects.

--------------------

==============================
== COMPREHENSION / APPLICATION
==============================

Name one advantage of using a parameterized list, i.e., a list that
can only take values of a certain type, over a list that can take
values of any type.

--------------------

What is the difference between a Java class and a Java interface?

--------------------

Given this partially-written implementation of an Array-based list
class, you are asked to write the reverse() method, which will reverse
the order of items in the list. Complete this method.  You may not
assume that anything other than what is here is implemented, but you
may add methods if you feel you need them. (Hint: you shouldn't need
to write more methods.)

public class ArrayList {

    Object[] elements;
    int index;

    public ArrayList() {
        elements = new Object[20];
        index = 0;
    }

    public void add(Object obj) {
        elements[index] = obj;
        index++;
    }

    public Object removeLast() {
        index--;
        return elements[index+1];
    }

    public void reverse() {
        // add your code here.




    }

}

--------------------

Given the following definition of a Customer, write a compareTo method
that will order Customers by their current account balances.

public class Customer implements Comparable<Customer> {
    String name;
    double balance;

    ...

    // Write the compareTo method here

}


==============================
== PROBLEM SOLVING
==============================

Suppose you're writing a program that stores a number of objects.
Give one reason you would use an array rather than a list to store the
objects. 

--------------------

Write a method findLowBalances() for the Customer class that takes a
list of Customers and a (double) threshold and returns a new list
consisting of all the Customers in the input list whose balance is
less than the threshold.

--------------------

Suppose you're writing a geographical information system.  Among other
things, the program needs to keep track of information about the 7
continents -- Africa, Antarctica, Asia, Australia, Europe, North
America, South America -- including their area, population, and
countries.  What Java entities would you use to represent the
continents?  Explain your answer.

--------------------

Write a method sameEnds(int[] nums, int n) that returns true if the
sequence of N numbers at the start and end of nums are the same. For
example, with nums = {5, 6, 45, 99, 13, 5, 6}, the ends are the same
for n=0 and n=2, and false for n=1 and n=3.  You may assume 
0 <= n <= nums.length.