Week 7: exam review
2013-03-03Exam 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
- 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; } }
- What does the following code print?
int x = 5; for (int i = 0; i < 5; i++) { x = x + i; if (x % 2 == 0) { System.out.println(x); } }
- Write a program that reads user input until the user enters a blank line, and the prints the longest line entered.
- Consider the
Callable
inteface defined below:
Implement this interface in a class calledpublic interface Callable { public int call(); }
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++) { System.out.println(f.call()); }
-
Define a class that has a method called
randomString
that takes a non-negative integer as input and returns aString
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'
.