Java Reference
In-Depth Information
Objects contain methods that implement their behavior. To
call a method on an object, write its name, followed by a
dot, followed by the method name.
Some programs are interactive and respond to input from
the user. These programs should print a message to the
user, also called a prompt, asking for the input.
A
String
object holds a sequence of characters. The char-
acters have indexes, starting with 0 for the first character.
Java has a class called
Scanner
that reads input from the
keyboard. A
Scanner
can read various pieces of input
(also called tokens) from an input source. It can read
either one token at a time or an entire line at a time.
An exception is an error that occurs when a program has
performed an illegal action and is unable to continue exe-
cuting normally.
Self-Check Problems
Section 3.1: Parameters
1.
What output is produced by the following program?
1
public class
Odds {
2
public static void
main(String[] args) {
3 printOdds(3);
4 printOdds(17 / 2);
5
6
int
x = 25;
7 printOdds(37 - x + 1);
8 }
9
10
public static void
printOdds(
int
n) {
11
for
(
int
i = 1; i <= n; i++) {
12
int
odd = 2 * i - 1;
13 System.out.print(odd + " ");
14 }
15 System.out.println();
16 }
17 }
2.
What is the output of the following program?
1
public
class Weird {
2
public static void
main(String[] args) {
3
int
number = 8;
4 halfTheFun(11);
5 halfTheFun(2 - 3 + 2 * 8);
6 halfTheFun(number);
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