Kapitel 2 Flashcards
1
// A crazy mixed up program public class Columbus
{
public static void main(String[] args) {
System.out.println("In 1492 Columbus sailed the ocean blue.");
}
}2
Columbus.java
3
public class Hello
{
public static void main(String[] args) {
System.out.println("Hello World");
}
}4
// Example // August 22, 2013
public class MyName {
public static void main(String[] args) { System.out.println("Herbert Dorfmann");
}
}5
C
6
A
7
// Its a mad, mad program public class Success
{
public static void main(String[] args)
{ System.out.print("Success\n"); System.out.print("Success "); System.out.print("Success\n"); System.out.println("\nSuccess");
} }8
The works of Wolfgang include the following
The Turkish March and Symphony No. 40 in G minor.
9
// August 22, 2013
public class PersonalInfo
{
public static void main(String[] args)
{
System.out.println("Herbert Dorfmann");
System.out.println("123 Elm Street");
System.out.println("My Town, NC 21111");
System.out.println("919-555-1234");
}
}10
Variables: little big Literals: 2 2000 "The little number is " "The big number is "
11
The value is number
12
99bottles is illegal because it starts with a number.
r&d is illegal because the & character is illegal.
13
They are not the same because one begins with an uppercase S while the other
begins with a lowercase s. Variable names are case-sensitive.
14
a) short
b) int
c) 22.1 because it is stored as a double .
15
6.31E17
16
Append the F suffix to the numeric literal, such as:
number = 7.4F;
17
true and false
18
a) char letter;
b) letter = ‘A’;
c) System.out.println(letter);
19
The code for ‘C’ is 67.
The code for ‘F’ is 70.
The code for ‘W’ is 87.
20
‘B’ is a character literal.
21
You cannot assign a string literal to a char variable. The statement should be:
char letter = ‘Z’;
22
Expression Value 6 + 3 * 5 21 12 / 2 - 4 2 9 + 14 * 2 - 6 31 5 + 19 % 3 - 1 5 (6 + 2) * 3 24 14 / (11 - 4) 2 9 + 12 * (8 - 3) 69
23
Integer division. The value 23.0 will be stored in portion .
24
a) x += 6;
b) amount -= 4;
c) y *= 4;
d) total /= 27;
e) x %= 7;
25
a) No
b) Because the result of basePay + bonus results in an int value, which cannot be
stored in the short variable totalPay . You can fix the problem by declaring
totalPay as an int , or casting the result of the expression to a short .
26
a = (float)b;
27
String city = “San Francisco”;
28
stringLength = city.length();
29
oneChar = city.charAt(0);
30
upperCity = city.toUpperCase();
31
lowerCity = city.toLowerCase();
32
To write a single line comment you begin the comment with // . To write a multi-line
comment you begin the comment with /* and end it with */ . To write a documentation
comment you begin the comment with /** and end it with */ .
33
Documentation comments can be read and processed by a program named
javadoc . The javadoc program can read Java source code files and generate
attractively formatted HTML documentation files. If the source code files contain
any documentation comments, the information in the comments becomes part of
the HTML documentation.
34
A message dialog box is used to display a message to the user. An input dialog box
is used to gather keyboard input from the user.
35
a) JOptionPane.showMessageDialog(null, “Greetings Earthling.”);
b) str = JOptionPane.showInputDialog(“Enter a number.”);
36
String str;
int age;
str = JOptionPane.showInputDialog(“Enter your age.”);
age = Integer.parseInt(str);
37
import javax.swing.JOptionPane;
