Programming Tools & Computer Science I

CSC 185 & 201, Spring 2013, Northern Virginia Community College

Week 8: exam review


Exam 1 (on Wednesday, March 6) will cover all the review material, plus design and implementation of classes and interfaces. This corresponds roughly to book chapters 1-7, plus parts of 8.

Example problems

  1. Add an equals method to the class below that represents a fraction. The method should return true if the two fractions represent the same number.
    public class Fraction {
        // Represent the number n/d.
        public final int n; // numerator
        public final int d; // denominator
        public Fraction(int n, int d) {
            this.n = n;
            this.d = d;
  2. What does the following code print?
    int x = 5;
    for (int i = 0; i < 5; i++) {
        x  = x + i;
        if (x % 2 == 0) {
  3. Write a program that reads user input until the user enters a blank line, and the prints the longest line entered.
  4. Consider the Callable inteface defined below:
    public interface Callable {
        public int call();
    Implement this interface in a class called Inc so that the output of the following program is the numbers 1 through 10:
    Callable f = new Inc();
    for (int = 0; i < 10; i++) {
  5. Define a class that has a method called randomString that takes a non-negative integer as input and returns a String made up of random letters in the range a-z.

    The standard library Random class could be helpful. Another useful fact: in Java, computing (char)('a' + 1) results in 'b'.