Introduction to Java Programming, Seventh Edition, Y. Daniel Liang
Chapter 2 Elementary Programming
Section 2.3 Identifiers
1
Every letter in a Java keyword is in lowercase?
A.
true
B.
false
2
Which of the following is a valid identifier?
A.
$343
B.
class
C.
9X
D.
8+9
E.
radius
Section 2.4 Variables
3
Which of the following are correct names for variables according to Java naming conventions?
A.
radius
B.
Radius
C.
RADIUS
D.
findArea
E.
FindArea
4
Which of the following are correct ways to declare variables?
A.
int length; int width;
B.
int length, width;
C.
int length; width;
D.
int length, int width;
Section 2.5 Assignment Statements and Assignment Expressions
5
____________ is the Java assignment operator.
A.
==
B.
:=
C.
=
D.
=:
6
To assign a value 1 to variable x, you write
A.
1 = x;
B.
x = 1;
C.
x := 1;
D.
1 := x;
E.
x == 1;
7
Which of the following assignment statements is incorrect.
A.
i = j = k = 1;
B.
i = 1; j = 1; k = 1;
C.
i = 1 = j = 1 = k = 1;
D.
i == j == k == 1;
Section 2.6 Constants
8
To declare a constant MAX_LENGTH inside a method with value 99.98, you write
A.
final MAX_LENGTH = 99.98;
B.
final float MAX_LENGTH = 99.98;
C.
double MAX_LENGTH = 99.98;
D.
final double MAX_LENGTH = 99.98;
9
Which of the following is a constant, according to Java naming conventions?
A.
MAX_VALUE
B.
Test
C.
read
D.
ReadInt
E.
COUNT
10
To improve readability and maintainability, you should declare _________ instead of using literal values such as 3.14159.
A.
variables
B.
methods
C.
constants
D.
classes
Section 2.7 Numeric Data Types and Operations
11
Which of these data type requires the most amount of memory?
A.
long
B.
int
C.
short
D.
byte
12
To declare an int variable number with initial value 2, you write
A.
int number = 2L;
B.
int number = 2l;
C.
int number = 2;
D.
int number = 2.0;
13
What is the result of 45 / 4?
A.
10
B.
11
C.
11.25
D.
12
14
Which of the following expressions will yield 0.5?
A.
1 / 2
B.
1.0 / 2
C.
(double) (1 / 2)
D.
(double) 1 / 2
E.
1 / 2.0
15
Which of the following expression results in a value 1?
A.
2 % 1
B.
15 % 4
C.
25 % 5
D.
37 % 6
16
25 % 1 is _____
A.
1
B.
2
C.
3
D.
4
E.
0
17
-25 % 5 is _____
A.
1
B.
2
C.
3
D.
4
E.
0
18
24 % 5 is _____
A.
1
B.
2
C.
3
D.
4
E.
0
19
-24 % 5 is _____
A.
-1
B.
-2
C.
-3
D.
-4
E.
0
20
-24 % -5 is _____
A.
3
B.
-3
C.
4
D.
-4
E.
0
21
To add a value 1 to variable x, you write
A.
1 + x = x;
B.
x += 1;
C.
x := 1;
D.
x = x + 1;
E.
x = 1 + x;
22
To add number to sum, you write (Note: Java is case-sensitive)
A.
number += sum;
B.
number = sum + number;
C.
sum = Number + sum;
D.
sum += number;
E.
sum = sum + number;
23
Suppose x is 1. What is x after x += 2?
A.
0
B.
1
C.
2
D.
3
E.
4
24
Suppose x is 1. What is x after x -= 1?
A.
0
B.
1
C.
2
D.
-1
E.
-2
25
What is x after the following statements?
int x = 1;
int y = 2;
x *= y + 1;
A.
x is 1;
B.
x is 2;
C.
x is 3;
D.
x is 4;
26
What is x after the following statements?
int x = 1;
x *= x + 1;
A.
x is 1;
B.
x is 2;
C.
x is 3;
D.
x is 4;
27
Analyze the following code.
public class Test {
public static void main(String[] args) {
int month = 09;
System.out.println("month is " + month);
}
}
A.
The program displays month is 09
B.
The program displays month is 9
C.
The program displays month is 9.0
D.
The program has a syntax error, because 09 is an incorrect literal value.
28
What is y displayed in the following code?
public class Test1 {
public static void main(String[] args) {
int x = 1;
int y = x = x + 1;
System.out.println("y is " + y);
}
}
A.
y is 0.
B.
y is 1 because x is assigned to y first.
C.
y is 2 because x + 1 is assigned to x and then x is assigned to y.
D.
The program has a compile error since x is redeclared in the statement int y = x = x + 1.
29
What is i printed?
public class Test {
public static void main(String[] args) {
int j = 0;
int i = ++j + j * 5;
System.out.println("What is i? " + i);
}
}
A.
0
B.
1
C.
5
D.
6
30
What is i printed in the following code?
public class Test {
public static void main(String[] args) {
int j = 0;
int i = j++ + j * 5;
System.out.println("What is i? " + i);
}
}
A.
0
B.
1
C.
5
D.
6
31
What is y displayed in the following code?
public class Test {
public static void main(String[] args) {
int x = 1;
int y = x++ + x;
System.out.println("y is " + y);
}
}
A.
y is 1.
B.
y is 2.
C.
y is 3.
D.
y is 4.
32
What is y displayed?
public class Test {
public static void main(String[] args) {
int x = 1;
int y = x + x++;
System.out.println("y is " + y);
}
}
A.
y is 1.
B.
y is 2.
C.
y is 3.
D.
y is 4.
Section 2.8 Numeric Type Conversions
33
To assign a double variable d to a float variable x, you write
A.
x = (long)d
B.
x = (int)d;
C.
x = d;
D.
x = (float)d;
34
What is the printout of the following code:
double x = 5.5;
int y = (int)x;
System.out.println("x is " + x + " and y is " + y);
A.
x is 5 and y is 6
B.
x is 6.0 and y is 6.0
C.
x is 6 and y is 6
D.
x is 5.5 and y is 5
E.
x is 5.5 and y is 5.0
35
Which of the following assignment statements is illegal?
A.
float f = -34;
B.
int t = 23;
C.
short s = 10;
D.
int t = (int)false;
E.
int t = 4.5;
36
What is the value of (double)5/2?
A.
2;
B.
2.5;
C.
3;
D.
2.0;
E.
3.0;
37
What is the value of (double)(5/2)?
A.
2;
B.
2.5;
C.
3;
D.
2.0;
E.
3.0;
38
If you attempt to add an int, a byte, a long, and a double, the result will be a __________ value.
A.
byte
B.
int
C.
long
D.
double
Section 2.9 Character Data Type and Operations
39
Which of the following is the correct expression of character 4?
A.
4
B.
"4"
C.
'\0004'
D.
'4'
40
A Java character is stored in __________.
A.
one byte
B.
two bytes
C.
three bytes
D.
four bytes
41
Suppose x is a char variable with a value 'b'. What is the printout of the statement System.out.println(++x)?
A.
a
B.
b
C.
c
D.
d
42
Which of the following statement prints smith\exam1\test.txt?
A.
System.out.println("smith\exam1\test.txt");
B.
System.out.println("smith\\exam1\\test.txt");
C.
System.out.println("smith\"exam1\"test.txt");
D.
System.out.println("smith"\exam1"\test.txt");
43
Suppose i is an int type variable. Which of the following statements display the character whose Unicode is stored in variable i?
A.
System.out.println(i);
B.
System.out.println((char)i);
C.
System.out.println((int)i);
D.
System.out.println(i + " ");
44
The Unicode of 'a' is 97. What is the Unicode for 'c'?
A.
96
B.
97
C.
98
D.
99
45
Will System.out.println((char)4) display 4?
A.
Yes
B.
No
46
What is the printout of System.out.println('z' - 'a')?
A.
25
B.
26
C.
a
D.
z
47
An int variable can hold __________.
A.
'x'
B.
120
C.
120.0
D.
"x"
E.
"120"
48
Which of the following assignment statements is correct?
A.
char c = 'd';
B.
char c = 100;
C.
char c = "d";
D.
char c = "100";
Section 2.10 The String Type
49
The expression "Java " + 1 + 2 + 3 evaluates to ________.
A.
Java123
B.
Java6
C.
Java 123
D.
java 123
E.
Illegal expression
50
Note that the Unicode for character A is 65. The expression "A" + 1 evaluates to ________.
A.
66
B.
B
C.
A1
D.
Illegal expression
51
Note that the Unicode for character A is 65. The expression 'A' + 1 evaluates to ________.
A.
66
B.
B
C.
A1
D.
Illegal expression
Section 2.11 Console Input Using the Scanner Class
52
Suppose a Scanner object is created as follows:
Scanner input = new Scanner(System.in);
What method do you use to read an int value?
A.
input.nextInt();
B.
input.nextInteger();
C.
input.int();
D.
input.integer();
53
The following code fragment reads in two numbers:
Scanner input = new Scanner(System.in);
int i = input.nextInt();
double d = input.nextDouble();
What are the correct ways to enter these two numbers?
A.
Enter an integer, a space, a double value, and then the Enter key.
B.
Enter an integer, two spaces, a double value, and then the Enter key.
C.
Enter an integer, an Enter key, a double value, and then the Enter key.
D.
Enter a numeric value with a decimal point, a space, an integer, and then the Enter key.
54
If you enter 1 2 3, when you run this program, what will be the output?
import java.util.Scanner;
public class Test1 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter three numbers: ");
double number1 = input.nextDouble();
double number2 = input.nextDouble();
double number3 = input.nextDouble();
// Compute average
double average = (number1 + number2 + number3) / 3;
// Display result
System.out.println(average);
}
}
A.
1.0
B.
2.0
C.
3.0
D.
4.0
Section 2.12 Case Studies
55
Math.pow(2, 3) returns __________.
A.
9
B.
8
C.
9.0
D.
8.0
56
The __________ method returns a raised to the power of b.
A.
Math.power(a, b)
B.
Math.exponent(a, b)
C.
Math.pow(a, b)
D.
Math.pow(b, a)
57
The expression (int)(76.0252175 * 100) / 100 evaluates to _________.
A.
76.02
B.
76
C.
76.0252175
D.
76.03
58
The System.currentTimeMillis() returns ________________ .
A.
the current time.
B.
the current time in milliseconds.
C.
the current time in milliseconds since midnight.
D.
the current time in milliseconds since midnight, January 1, 1970.
E.
the current time in milliseconds since midnight, January 1, 1970 GMT (the Unix time).
Section 2.13 Programming Style and Documentation
59
Programming style is important, because ______________.
A.
a program may not compile if it has a bad style
B.
good programming style can make a program run faster
C.
good programming style makes a program more readable
D.
good programming style helps reduce programming errors
60
According to Java naming convention, which of the following names can be variables?
A.
FindArea
B.
findArea
C.
totalLength
D.
TOTAL_LENGTH
E.
class
Section 2.14 Programming Errors
61
If a program compiles fine, but it produces incorrect result, then the program suffers __________.
A.
a compilation error
B.
a runtime error
C.
a logic error
Section 2.16 (GUI) Getting Input from Input Dialogs
62
The __________ method displays an input dialog for reading a string.
A.
String string = JOptionPane.showMessageDialog(null, "Enter a string", "Input Demo", JOptionPane.QUESTION_MESSAGE);
B.
String string = JOptionPane.showInputDialog(null, "Enter a string", "Input Demo", JOptionPane.QUESTION_MESSAGE);
C.
String string = JOptionPane.showInputDialog("Enter a string", "Input Demo", JOptionPane.QUESTION_MESSAGE);
D.
String string = JOptionPane.showInputDialog(null, "Enter a string");
E.
String string = JOptionPane.showInputDialog("Enter a string");
63
The __________ method parses a string s to an int value.
A.
integer.parseInt(s);
B.
Integer.parseInt(s);
C.
integer.parseInteger(s);
D.
Integer.parseInteger(s);
64
The __________ method parses a string s to a double value.
A.
double.parseDouble(s);
B.
Double.parsedouble(s);
C.
double.parse(s);
D.
Double.parseDouble(s);
65
Analyze the following code.
import javax.swing.*;
public class ShowErrors {
public static void main(String[] args) {
int i;
int j;
String s = JOptionPane.showInputDialog(null,
"Enter an integer", "Input",
JOptionPane.QUESTION_MESSAGE);
j = Integer.parseInt(s);
i = (i + 4);
}
}
A.
The program cannot compile because j is not initialized.
B.
The program cannot compile because i does not have an initial value when it is used in i = i + 4;
C.
The program compiles but has a runtime error because i does not have an initial value when it is used in i = i + 4;
D.
The program compiles and runs fine.