Test Bank for Introduction to Java Programming and Data Structures, Comprehensive Version, 12th Edition

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 key:c See the second paragraph in this section. # 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 Key:c The first print statement prints a string followed by the second print statement that prints a number. # 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(); Key:a The correct method to read a real number is nextDouble(). # 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. Key:d See Listing 2.3. # 5. If you enter 1 2 3, when you run this program, what will be the output? import java.util.Scanner; © 2020 Pearson Education, Inc., Hoboken, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. 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 Key:b (1.0 + 2.0 + 3.0) / 3 is 2.0 # Section 2.4 Identifiers 6. Every letter in a Java keyword is in lowercase? a. true b. false Key:a It is true that the keywords in Java are in lowercase. For example, public, static, int, double, and void are the keywords. # 7. Which of the following is a valid identifier? a. $343 b. class c. 9X d. 8+9 e. radius Key:ae class is a keyword, which cannot be used as an identifier. Identifiers cannot start with a number. # 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 Key:ad A single-word variable is in lowercase. In a multiple-word variable, the words are concatenated with the first word in lowercase and the first letter of each subsequent word in uppercase. # 9. a. b. Which of the following are correct ways to declare variables? int length; int width; int length, width; © 2020 Pearson Education, Inc., Hoboken, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. c. int length; width; d. int length, int width; Key:ab Note that a semicolon ends a statement. In B, length and width are both declared as int. # Section 2.6 Assignment Statements and Assignment Expressions 10. is the Java assignment operator. a. == b. := c. = d. =: Key:c See the first paragraph. # 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; Key:b See the first paragraph. # 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; Key:cd Read toward the end of the section. # 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; Key:d See the first paragraph. # 14. Which of the following is a constant, according to Java naming conventions? a. MAX_VALUE b. Test c. read d. ReadInt e. COUNT Key:ae All letters in a constant are in uppercase. In a multiple-word constant, the words are connected using underscores. # 15. To improve readability and maintainability, you should declare a such as 3.14159. a. variable b. method for PI instead of using literal values © 2020 Pearson Education, Inc., Hoboken, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. c. constant d. class Key:c A constant gives a literal a descriptive name and makes the code more readable. # 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 Key:bc The first word in a variable is in lowercase. So B and C are correct. # 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 Key:a long takes 8 bytes. int 4 bytes. short 2 bytes. byte 1 byte. # Section 2.9.2 Numeric Operators 19. What is the result of 45 / 4? a. 10 b. 11 c. 11.25 d. 12 Key:b The result of the division is the quotient and the fractional part is truncated. So 45 / 4 is 11. 3 / 2 is 1, and so on. # 20. Which of the following expression results in a value 1? a. 2 % 1 b. 15 % 4 c. 25 % 5 d. 37 % 6 Key:d 2 % 1 is 0, 15 % 4 is 3, 25 % 5 is 0, and 37 % 6 is 1 # 21. 25 % 1 is a. 1 b. 2 c. 3 d. 4 e. 0 Key:e The reminder of any integer by 1 is 0. # 22. -25 % 5 is a. 1 b. 2 c. 3 © 2020 Pearson Education, Inc., Hoboken, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. d. 4 e. 0 Key:e # 23. 24 % 5 is a. 1 b. 2 c. 3 d. 4 e. 0 Key:d # 24. -24 % 5 is a. -1 b. -2 c. -3 d. -4 e. 0 Key:d # 25. -24 % -5 is a. 3 b. -3 c. 4 d. -4 e. 0 Key:d # 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 Key:b See the first paragraph of the section. # 27. Math.pow(2, 3) returns a. 9 b. 8 c. 9.0 d. 8.0 Key:d It returns a double value 8.0. # 28. Math.pow(4, 1 / 2) returns a. 2 b. 2.0 c. 0 . . © 2020 Pearson Education, Inc., Hoboken, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. d. 1.0 e. 1 Key:d Note that 1 / 2 is 0. # 29. Math.pow(4, 1.0 / 2) returns . a. 2 b. 2.0 c. 0 d. 1.0 e. 1 Key:b Note that the pow method returns a double value, not an integer. # 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) Key:c See line 1 in Section 2.9.3. # 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. Key:d Any numeric literal with the prefix 0 is an octal value. But 9 is not an octal digit. An octal digit is 0, 1, 2, 3, 4, 5, 6, or 7. # 33. Which of the following is incorrect? a. 1_2 b. 0.4_56 c. 1_200_229 d. _4544 Key:d You can use the digit separator _ for integers or floating point numbers. The separator must be placed between the digits. # 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 Key:abcd See Section 2.10.3. © 2020 Pearson Education, Inc., Hoboken, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. # 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; Key:c See Section 2.10.1. # 35. Which of the following is incorrect? a. int x = 9; b. long x = 9; c. float x = 1.0; d. double x = 1.0; Key:c Section 2.10.2. # Section 2.11 Prototyping Using JShell 31. The command to exit JShell is a. quit b. exit c. /quit d. /exit Key:d Read toward the end of this section. . # 31. The command to view all variables in JShell is a. vars b. var c. /vars d. /var Key:c See Figure 2.5. . # Section 2.12 Evaluating Expressions and Operator Precedence 36. The expression 4 + 20 / (3 – 1) * 2 is evaluated to a. 4 b. 20 c. 24 d. 9 e. 25 Key:c See the second paragraph in this section. # 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). Key:e See Listing 2.7. © 2020 Pearson Education, Inc., Hoboken, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. # 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 Key:c See Listing 2.7. # 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 Key:d See Listing 2.7. # 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 Key:e See Listing 2.7. # Section 2.14 Augmented Assignment Operators 43. Suppose x is 1. What is x after x += 2? a. 0 b. 1 c. 2 d. 3 e. 4 Key:d See Table 2.4 # 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 # 45. What is x after the following statements? int x = 2; int y = 1; x *= y + 1; a. x is 1. © 2020 Pearson Education, Inc., Hoboken, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. b. x is 2. c. x is 3. d. x is 4. Key:d (y + 1) is executed first and its result is multiplied with x and assigned to x. # 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. Key:b See Table 2.4. # 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 Key:b See Table 2.4. # 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; Key:bde See Table 2.4. # 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; Key:de See Table 2.4. # Section 2.15 Increment and Decrement Operators 49. What is i printed? public class Test { public static void main(String[] args) { © 2020 Pearson Education, Inc., Hoboken, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. int j = 0; int i = ++j + j * 5; System.out.println(“What is i? ” + i); } } a. 0 b. 1 c. 5 d. 6 Key:d Operands are evaluated from left to right in Java. The left-hand operand of a binary operator is evaluated before any part of the right-hand operand is evaluated. This rule takes precedence over any other rules that govern expressions. Therefore, ++j is evaluated first, and j is now 1. Then j * 5 is evaluated, returns 5. So, i is 6. # 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 Key:c Operands are evaluated from left to right in Java. The left-hand operand of a binary operator is evaluated before any part of the right-hand operand is evaluated. This rule takes precedence over any other rules that govern expressions. Therefore, j++ is evaluated first. j is now 1. Since j++ is postincrement, the old value of j is returned for j++. So j++ + j * 5 equals 0 + 1 * 5. So, the result is 5. # 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. Key:c When evaluating x++ + x, x++ is evaluated first, which does two things: 1. returns 1 since it is post-increment. x becomes 2. Therefore y is 1 + 2. # 52. What is y displayed? © 2020 Pearson Education, Inc., Hoboken, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. 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. Key:b When evaluating x + x++, x is evaluated first, which is 1. X++ returns 1 since it is post-increment and 2. Therefore y is 1 + 1. # 48. Are the following four statements equivalent? number += 1; number = number + 1; number++; ++number; a. Yes b. No Key:a See Table 2.5. # 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; Key:d See the second paragraph in this section. # 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 Key:bde 1 / 2 is an integer division, which results in 0. # 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 © 2020 Pearson Education, Inc., Hoboken, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. Key:d The value is x is not changed after the casting. # 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; Key:d See the second paragraph in this section. # 57. What is the value of (double)5/2? a. 2 b. 2.5 c. 3 d. 2.0 e. 3.0 Key:b See the second code box in this section. # 58. What is the value of (double)(5/2)? a. 2 b. 2.5 c. 3 d. 2.0 e. 3.0 Key:d See the second paragraph in this section. # 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 Key:b See Listing 2.8. # 60. The expression (int)(76.0252175 * 100) / 100 evaluates to a. 76.02 b. 76 c. 76.0252175 d. 76.03 Key:b In order to obtain 76.02, you have divide 100.0. . # 61. If you attempt to add an int, a byte, a long, and a double, the result will be a(n) a. byte b. int c. long d. double Key:d See the second paragraph in this section. value. # Section 2.17 Software Life Cycle © 2020 Pearson Education, Inc., Hoboken, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. 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 Key:a See the second paragraph in this section. # 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 Key:b See the third paragraph in this section. # 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 Key:c 3264 / 10 is 326 and 3264 % 10 is 4. # 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. © 2020 Pearson Education, Inc., Hoboken, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist. Key:c See Common Error 2: Integer Overflow. # 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 Key:e For example, byte b = 23232 will cause a compile error. © 2020 Pearson Education, Inc., Hoboken, NJ. All rights reserved. This material is protected under all copyright laws as they currently exist.