CHAPTER 4 (42-65) REVIEW QUESTIONS

Question 1

42. T F The = operator and the = = operator perform the same operation when used in a Boolean expression.

Answer 1

42. false

Question 2

43. T F A variable defined in an inner block may not have the same name as a variable defined in the outer block.

Answer 2

43. false

Question 3

44. T F A conditionally executed statement should be indented one level from the if statement.

Answer 3

44. true

Question 4

45. T F All lines in a block should be indented one level.

Answer 4

45. true

Question 5

46. T F It’s safe to assume that all uninitialized variables automatically start with 0 as their value.

Answer 5

46. false

Question 6

47. T F When an if statement is nested in the if part of another statement, the only time the inner if is executed is when the expression of the outer if is true.

Answer 6

47. true

Question 7

48. T F When an if statement is nested in the else part of another statement, as in an if/else if , the only time the inner if is executed is when the expression of the outer if is true.

Answer 7

48. false

Question 8

49. T F The scope of a variable is limited to the block in which it is defined.

Answer 8

49. true

Question 9

50. T F You can use the relational operators to compare string objects.

Answer 9

50. true

Question 10

51. T F x != y is the same as (x > y || x < y)

Answer 10

51. true

Question 11

52. T F y < x is the same as x >= y

Answer 11

52. false

Question 12

53. T F x >= y is the same as (x > y && x = y)

Answer 12

53. false

Question 13

Assume the variables x = 5 , y = 6 , and z = 8 . Indicate by circling the T or F whether each of the following conditions is true or false:
54. T F x == 5 || y > 3
55. T F 7 <= x && z > 4
56. T F 2 != y && z != 4
57. T F x >= 0 || x <= y

Answer 13

54. T
55. F
56. T
57. T

Question 14

Find the Errors, Each of the following programs has errors. Find as many as you can.
58. // This program averages 3 test scores.
include <iostream>
using namespace std;
int main()
{
cout << "Enter your 3 test scores and I will ";
<< "average them:";
int score1, score2, score3,
cin >> score1 >> score2 >> score3;
double average;
average = (score1 + score2 + score3) / 3.0;
if (average = 100);
perfectScore = true; // Set the flag variable
cout << "Your average is " << average << endl;
bool perfectScore;
if (perfectScore);
{
cout << "Congratulations!\n";
cout << "That's a perfect score.\n";
cout << "You deserve a pat on the back!\n";
return 0;
}</iostream>

Answer 14

58. The first cout statement is terminated by a semicolon too early.

The definition of score1, score2, and score3 should end with a semicolon.

The following statement:
if (average = 100)
should read:
if (average == 100)

perfectScore is used before it is defined.

The following if statement should not be terminated with a semicolon:
if (perfectScore);

The conditionally executed block in this if statement should end with a closing brace.

Question 15

59. // This program divides a user-supplied number by another
    // user-supplied number. It checks for division by zero.
    #include <iostream>
    using namespace std;
    int main()
    {
    double num1, num2, quotient;
    cout << "Enter a number: ";
    cin >> num1;
    cout << "Enter another number: ";
    cin >> num2;
    if (num2 = = 0)
    cout << "Division by zero is not possible.\n";
    cout << "Please run the program again ";
    cout << "and enter a number besides zero.\n";
    else
    quotient = num1 / num2;
    cout << "The quotient of " << num1 <<
    cout << " divided by " << num2 << " is ";
    cout << quotient << endl;
    return 0;
    }</iostream>

Answer 15

59. The conditionally executed blocks in the if/else construct should be enclosed in braces.

The following statement:
cout &laquo_space;“The quotient of “ &laquo_space;num1 «
should read:
cout &laquo_space;“quotient of “ &laquo_space;num1;

Question 16

60. // This program uses an if/else if statement to assign a
    // letter grade (A, B, C, D, or F) to a numeric test score.
    #include <iostream>
    using namespace std;
    int main()
    {
    int testScore;
    cout << "Enter your test score and I will tell you\n";
    cout << "the letter grade you earned: ";
    cin >> testScore;
    if (testScore < 60)
    cout << "Your grade is F.\n";
    else if (testScore < 70)
    cout << "Your grade is D.\n";
    else if (testScore < 80)
    cout << "Your grade is C.\n";
    else if (testScore < 90)
    cout << "Your grade is B.\n";
    else
    cout << "That is not a valid score.\n";
    else if (testScore <= 100)
    cout << "Your grade is A.\n";
    return 0;
    }</iostream>

Answer 16

60. The trailing else statement should come at the end of the if/else construct.

Question 17

61. // This program uses a switch-case statement to assign a
    // letter grade (A, B, C, D, or F) to a numeric test score.
    #include <iostream>
    using namespace std;
    int main()
    {
    double testScore;
    cout << "Enter your test score and I will tell you\n";
    cout << "the letter grade you earned: ";
    cin >> testScore;
    switch (testScore)
    {
    case (testScore < 60.0):
    cout << "Your grade is F.\n";
    break;
    case (testScore < 70.0):
    cout << "Your grade is D.\n";
    break;
    case (testScore < 80.0):
    cout << "Your grade is C.\n";
    break;
    case (testScore < 90.0):
    cout << "Your grade is B.\n";
    break;
    case (testScore <= 100.0):
    cout << "Your grade is A.\n";
    break;
    default:
    cout << "That score isn't valid\n";
    return 0;
    }</iostream>

Answer 17

61. A switch statement cannot be used to test relational expressions. An if/else if statement should be used instead.

Question 18

62. The following statement should determine if x is not greater than 20. What is wrong with it?
    if (!x > 20)

Answer 18

62. It should read if (!(x > 20))

Question 19

63. The following statement should determine if count is within the range of 0 through

If(count >=0 && count <=100)

Answer 19

63. It should use && instead of ||.

Question 20

64. The following statement should determine if count is outside the range of 0 through

What is wrong with it?
if (count < 0 && count > 100)

Answer 20

64. It should read if (count < 0 || count > 100)

Question 21

65. The following statement should assign 0 to z if a is less than 10, otherwise it should assign 7 to z . What is wrong with it?
    z = (a < 10) : 0 ? 7;

Answer 21

65. The : and ? are transposed. The statement should read:
    z = (a < 10) ? 0 : 7;