Multiple Choice

Multiple Choice Section 3.1 The Bag ADT

1. For the bag class in Chapter 3 (using a fixed array and a typedef statement) what steps were necessary for changing from a bag of integers to a bag of double values?
   • A. Change the array declaration from int data[CAPACITY] to double data[CAPACITY] and recompile.
   • B. Change the int to double in the typedef statement and recompile.
   • C. Round each double value to an integer before putting it in the bag.
   • D. Round each double value to an integer after taking it out of the bag.

2. Who needs to know about the invariant of an ADT?
   • A. Only the programmer who implements the class for the ADT.
   • B. Only the programmer who uses the class for the ADT.
   • C. Both the programmer who implements the class and the programmer who uses the class.
   • D. Neither the programmer who implements the class nor the programmer who uses the class.

3. Suppose that the bag is implemented with a fixed-size array. Which of these operations are likely to have a constant worst-case time?
   • A. insert
   • B. count
   • C. erase_one
   • D. None of (A), (B), and (C) have a constant worst-case time
   • E. TWO of (A), (B), and (C) have a constant worst-case time
   • F. ALL of (A), (B), and (C) have a constant worst-case time

4. Suppose that foo is a new class and you want to declare an array of 10 foo objects. Which constructor will be used to initialize the 10 foo components of the array?
   • A. Only the copy constructor can be used
   • B. Only the default constructor can be used
   • C. Any constructor can be used

5. Suppose that the bag class is efficiently implemented with a fixed array with a capacity of 4000, as in Chapter 3 of the class text. Choose the best description of b's member variables after we execute these statements:

    bag b; b.insert(5); b.insert(4); b.insert(6); 

   What will be the values of b.used and b.data after the statements?
   • A. b.used is 3, b.data[0] is 4, b.data[1] is 5, and b.data[2] is 6
   • B. b.used is 3, b.data[0] is 5, b.data[1] is 4, and b.data[2] is 6
   • C. b.used is 3, b.data[0] is 6, b.data[1] is 4, and b.data[2] is 5
   • D. b.used is 3, b.data[0] is 6, b.data[1] is 5, and b.data[2] is 4

6. Suppose that the bag class is efficiently implemented with a fixed array with a capacity of 4000, as in Chapter 3 of the class text. We execute these statements:

    bag b; b.insert(5); b.insert(4); b.insert(6); b.erase_one(5); 

   • A. b.used is 2, b.data[0] is 4, b.data[1] is 6
   • B. b.used is 2, b.data[0] is 6, b.data[1] is 4
   • C. b.used is 3, b.data[0] is 4, b.data[1] is 6
   • D. b.used is 3, b.data[0] is 6, b.data[1] is 4

7. I have an array named data, which contains n integers. I want to print all of the numbers, starting at data[0]. BUT if the number 42 occurs, then I want to stop my printing just before the 42 (without printing the 42!) Here is most of my for-loop to accomplish my goal:

    for (i = 0; ___________________________________________; i++) cout << data[i] << endl; 

   What is the correct way to fill in the blank? (If there is more than one correct answer, please select E.)
   • A. (data[i] != 42) && (i < n)
   • B. (data[i] != 42) || (i < n)
   • C. (i < n) && (data[i] != 42)
   • D. (i < n) || (data[i] != 42)
   • E. More than one of the above answers is correct.

8. Suppose that you are working on a machine where arrays may have up to 4,000,000,000 items. What is the guaranteed range of the size_t data type?
   • A. Negative 4,000,000,000 to positive 4,000,000,000.
   • B. Zero to positive 32,767
   • C. Zero to positive 65,535
   • D. Zero to 4,000,000,000
   • E. Zero to 8,000,000,000

   Multiple Choice Section 3.2 The Sequence ADT

9. In Chapter 3, there was a suggested implementation of the sequence class with a fixed CAPACITY and these private member variables:

    class sequence { public: typedef double value_type; typedef std::size_t size_type; static const size_type CAPACITY = 30; ... private: value_type data[CAPACITY]; size_type used; }; 

   The sequence's constructor sets used to zero, but does not place any values in the data array. Why?
   • A. Integer arrays are automatically initialized to zero.
   • B. The first activation of insert or attach initializes the entire array.
   • C. The array initialization was part of the project that was left to the student.
   • D. The programmer who uses the sequence is responsible for initializing the array.
   • E. When a sequence is first created, none of the array is being used.

10. This question is appropriate if you implemented the sequence class. The sequence's insert member function normally puts a new item before the current item. What does insert do if there is no current item?
    • A. The insert precondition is violated.
    • B. The new item is put at the beginning of the sequence.
    • C. The new item is put at the end of the sequence.
    • D. None of the above.

11. Suppose that the sequence is implemented with a fixed-size array. Which of these operations are likely to have a constant worst-case time?
    • A. insert
    • B. count
    • C. erase_one
    • D. None of (A), (B), and (C) have a constant worst-case time
    • E. TWO of (A), (B), and (C) have a constant worst-case time
    • F. ALL of (A), (B), and (C) have a constant worst-case time

12. Suppose the bag and sequence are both implemented with a fixed-size array as in Chapter 3. What is the difference between the private member variables of the bag and the private member variables of the sequence?
    • A. The bag has an extra array of Items.
    • B. The bag has one extra size_t variable.
    • C. The sequence has an extra array of Items.
    • D. The sequence has one extra size_t variable.

13. Suppose that the bag and the sequence have both been implemented with partially filled arrays. Which statement is true about the worst-case run time of the erase_one operations.
    • A. Both removal functions have constant worst-case run times.
    • B. The bag's removal is constant time, but the sequence's removal is not.
    • C. The sequence's removal is constant time, but the bag's removal is not.
    • D. Neither removal function has constant worst-case run time.

14. Suppose that the bag is implemented with a fixed-size array. Which of these operations are likely to have a constant worst-case time?
    • A. insert
    • B. count
    • C. erase_one
    • D. TWO of the above are likely to have a constant worst-case time.
    • D. ALL of (A), (B), and (C) are likely to have a constant worst-case time.

    Multiple Choice Section 3.3 Interactive Test Programs

15. What is the best C++ statement to use when a program must choose between several alternatives that are controlled by the value of a single variable?
    • A. do-while statement
    • B. for-statement
    • C. if-else statement
    • D. switch statement
    • E. while statement