Chapter 2 Elementary Programming
Section 2.2 Writing a Simple Program
1. is the code with natural language mixed with Java code.
a. Java program
b. A Java statement
c. Pseudocode
d. A flowchart diagram
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2. What is the exact output of the following code?
double area = 3.5;
System.out.print(“area”);
System.out.print(area);
a. 3.53.5
b. 3.5 3.5
c. area3.5
d. area 3.5
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Section 2.3 Reading Input from the Console
3. Suppose a Scanner object is created as follows, what method do you use to read a real number?
Scanner input = new Scanner(System.in);
a. input.nextDouble();
b. input.nextdouble();
c. input.double();
d. input.Double();
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4. The following code fragment reads in two numbers. What is the incorrect way to enter these two numbers?
Scanner input = new Scanner(System.in);
int i = input.nextInt();
double d = input.nextDouble();
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.
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5. 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
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Section 2.4 Identifiers
6. Every letter in a Java keyword is in lowercase?
a. true
b. false
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7. Which of the following is a valid identifier?
a. $343
b. class
c. 9X
d. 8+9
e. radius
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Section 2.5 Variables
8. Which of the following are correct names for variables according to Java naming conventions?
a. radius
b. Radius
c. RADIUS
d. findArea
e. FindArea
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9. 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;
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Section 2.6 Assignment Statements and Assignment Expressions
10. is the Java assignment operator.
a. ==
b. :=
c. =
d. =:
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11. 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;
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12. 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;
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Section 2.7 Named Constants
13. 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;
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14. Which of the following is a constant, according to Java naming conventions?
a. MAX_VALUE
b. Test
c. read
d. ReadInt
e. COUNT
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15. To improve readability and maintainability, you should declare a for PI instead of using literal values
such as 3.14159.
a. variable
b. method
c. constant
d. class
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Section 2.8 Naming Conventions
16. According to Java naming convention, which of the following names can be variables?
a. FindArea
b. findArea
c. totalLength
d. TOTAL_LENGTH
e. class
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Section 2.9 Numeric Data Types and Operations
17. Which of these data types requires the most amount of memory?
a. long
b. int
c. short
d. byte
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Section 2.9.2 Numeric Operators
19. What is the result of 45 / 4?
a. 10
b. 11
c. 11.25
d. 12
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20. Which of the following expression results in a value 1?
a. 2 % 1
b. 15 % 4
c. 25 % 5
d. 37 % 6
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21. 25 % 1 is
a. 1
b. 2
c. 3
d. 4
e. 0
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22. –25 % 5 is
a. 1
b. 2
c. 3
d. 4
e. 0
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23. 24 % 5 is
a. 1
b. 2
c. 3
d. 4
e. 0
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24. –24 % 5 is
a. –1
b. –2
c. –3
d. –4
e. 0
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25. –24 % –5 is
a. 3
b. –3
c. 4
d. –4
e. 0
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Section 2.9.3 Exponent Operations
26. How do you write 2.5 ^ 3.1 in Java?
a. 2.5 * 3.1
b. Math.pow(2.5, 3.1)
c. Math.pow(3.1, 2.5)
d. 2.5 ** 3.1
e. 3.1 ** 2.5
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27. Math.pow(2, 3) returns .
a. 9
b. 8
c. 9.0
d. 8.0
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28. Math.pow(4, 1 / 2) returns .
a. 2
b. 2.0
c. 0
d. 1.0
e. 1
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29. Math.pow(4, 1.0 / 2) returns .
a. 2
b. 2.0
c. 0
d. 1.0
e. 1
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30. 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)
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Section 2.10 Numeric Literals
32. 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.
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33. Which of the following is incorrect?
a. 1_2
b. 0.4_56
c. 1_200_229
d. _4544
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34. Which of the following are the same as 1545.534?
a. 1.545534e+3
b. 0.1545534e+4
c. 1545534.0e–3
d. 154553.4e–2
36.
The expression 4 + 20 / (3 – 1) * 2 is evaluated to
a.
4
b.
20
c.
24
d.
9
e.
25
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31. 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;
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35. Which of the following is incorrect?
a. int x = 9;
b. long x = 9;
c. float x = 1.0;
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Section 2.11 Prototyping Using JShell
31. The command to exit JShell is .
a. \quit
b. \exit
c. /quit
d. /exit
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31. The command to view all variables in JShell is .
a. \vars
b. \var
c. /vars
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Section 2.12 Evaluating Expressions and Operator Precedence
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Section 2.13 Case Study: Displaying the Current Time
37. 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).
43.
Suppose x is 1. What is x after x += 2?
a.
0
b.
1
c.
2
d.
3
e.
4
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38. To obtain the current second, use .
a. System.currentTimeMillis() % 3600
b. System.currentTimeMillis() % 60
c. System.currentTimeMillis() / 1000 % 60
d. System.currentTimeMillis() / 1000 / 60 % 60
e. System.currentTimeMillis() / 1000 / 60 / 60 % 24
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39. To obtain the current minute, use .
a. System.currentTimeMillis() % 3600
b. System.currentTimeMillis() % 60
c. System.currentTimeMillis() / 1000 % 60
d. System.currentTimeMillis() / 1000 / 60 % 60
e. System.currentTimeMillis() / 1000 / 60 / 60 % 24
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40. To obtain the current hour in UTC, use .
a. System.currentTimeMillis() % 3600
b. System.currentTimeMillis() % 60
c. System.currentTimeMillis() / 1000 % 60
d. System.currentTimeMillis() / 1000 / 60 % 60
e. System.currentTimeMillis() / 1000 / 60 / 60 % 24
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Section 2.14 Augmented Assignment Operators
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44.
Suppose x is 1. What is x after x –= 1?
a.
0
b.
1
c.
2
d.
–1
e.
–2
Key:a See Table 2.4
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45. What is x after the following statements?
int x = 2;
int y = 1;
x *= y + 1;
a. x is 1.
b. x is 2.
c. x is 3.
d. x is 4.
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46. 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.
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47. Which of the following statements are the same?
(A) x –= x + 4
(B) x = x + 4 – x
(C) x = x – (x + 4)
a. (A) and (B) are the same
b. (A) and (C) are the same
c. (B) and (C) are the same
d. (A), (B), and (C) are the same
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41. 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;
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42. 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;
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Section 2.15 Increment and Decrement Operators
49. 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
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50. 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
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51. 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.
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52. 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.
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48. Are the following four statements equivalent?
number += 1;
number = number + 1;
number++;
++number;
a. Yes
b. No
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Section 2.16 Numeric Type Conversions
53. 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;
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54. 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
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55. What is the output 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
a.
2
b.
2.5
c.
3
d.
2.0
e.
3.0
a.
2
b.
2.5
c.
3
d.
2.0
e.
3.0
Key:d The value is x is not changed after the casting.
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56. Which of the following assignment statements is illegal?
a. float f = –34;
b. int t = 23;
c. short s = 10;
d. int t = 4.5;
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57. What is the value of (double)5/2?
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58. What is the value of (double)(5/2)?
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59. Which of the following expression results in 45.37?
a. (int)(45.378 * 100) / 100
b. (int)(45.378 * 100) / 100.0
c. (int)(45.378 * 100 / 100)
d. (int)(45.378) * 100 / 100.0
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60. The expression (int)(76.0252175 * 100) / 100 evaluates to .
a. 76.02
b. 76
c. 76.0252175
d. 76.03
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61. If you attempt to add an int, a byte, a long, and a double, the result will be a(n) value.
a. byte
b. int
c. long
d. double
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Section 2.17 Software Life Cycle
62. is a formal process that seeks to understand the problem and document in detail what the software
system needs to do.
a. Requirements specification
b. Analysis
c. Design
d. Implementation
e. Testing
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63. seeks to analyze the data flow and to identify the system’s input and output. When you do
analysis, it helps to identify what the output is first, and then figure out what input data you need in order to produce
the output.
a. Requirements specification
b. Analysis
c. Design
d. Implementation
e. Testing
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Section 2.18 Case Study: Counting Monetary
62. Suppose int x = 3264, what is the output of the following code?
int y = x % 10;
x = x / 10;
System.out.println(“x is ” + x + ” and y is ” + y);
a. x is 3264 and y is 326.4
b. x is 326 and y is 326
c. x is 326 and y is 4
d. x is 3264 and y is 4
e. x is 4 and y is 326
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Section 2.19 Common Errors and Pitfalls
64. Analyze the following code:
public class Test {
public static void main(String[] args) {
int n = 10000 * 10000 * 10000;
System.out.println(“n is ” + n);
}
}
a. The program displays n is 1000000000000.
b. The result of 10000 * 10000 * 10000 is too large to be stored in an int variable n. This causes an overflow and
the program is aborted.
c. The result of 10000 * 10000 * 10000 is too large to be stored in an int variable n. This causes an overflow and
the program continues to execute because Java does not report errors on overflow.
d. The result of 10000 * 10000 * 10000 is too large to be stored in an int variable n. This causes an underflow and
the program is aborted.
e. The result of 10000 * 10000 * 10000 is too large to be stored in an int variable n. This causes an underflow and the
program continues to execute because Java does not report errors on underflow.
Key:c See Common Error 2: Integer Overflow.
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18. When assigning a literal to a variable of the byte type, if the literal is too large to be stored as a byte value, it
.
a. causes overflow
b. causes underflow
c. causes no error
d. cannot happen in Java
e. receives a compile error