Multiple Choice

Multiple Choice Section 2.1 - 2.2 Introduction to Classes

1. Here is the start of a class declaration:

    class foo { public: void x(foo f); void y(const foo f); void z(foo f) const; ... 

   Which of the three member functions can alter the PRIVATE member variables of the foo object that activates the function?
   • A. Only x can alter the private member variables of the object that activates the function.
   • B. Only y can alter the private member variables of the object that activates the function.
   • C. Only z can alter the private member variables of the object that activates the function.
   • D. Two of the functions can alter the private member variables of the object that activates the function.
   • E. All of the functions can alter the private member variables of the object that activates the function.

2. Is it possible for a member function of a class to activate another member function of the same class?
   • A. No.
   • B. Yes, but only public member functions.
   • C. Yes, but only private member functions.
   • D. Yes, both public and private member functions can be activated within another member function.

3. Can two classes contain member functions with the same name?
   • A. No.
   • B. Yes, but only if the two classes have the same name.
   • C. Yes, but only if the main program does not declare both kinds
   • D. Yes, this is always allowed.

4. What is the common pattern of class definitions that is used in Chapter 2?
   • A. Member functions and member variables are both private.
   • B. Member functions are private, and member variables are public.
   • C. Member functions are public, and member variables are private.
   • D. Member functions and member variables are both public.

5. Consider this class definition:

    class quiz { public: quiz( ); int f( ); int g( ) const; private: double score; }; 

   Which functions can carry out an assignment score=1.0; to the private member variable score?
   • A. Both f and g can carry out the assignment.
   • B. f can carry out the assignment, but not g.
   • C. g can carry out the assignment, but not f.
   • D. Neither f nor g can carry out the assignment.

6. What is the primary purpose of a default constructor?
   • A. To allow multiple classes to be used in a single program.
   • B. To copy an actual argument to a function's parameter.
   • C. To initialize each object as it is declared.
   • D. To maintain a count of how many objects of a class have been created.

7. Suppose that the foo class does not have an overloaded assignment operator. What happens when an assignment a=b; is given for two foo objects?
   • A. The automatic assignment operator is used
   • B. The copy constructor is used
   • C. Compiler error
   • D. Run-time error

   Multiple Choice Section 2.4 Classes and Parameters

8. When should you use a const reference parameter?
   • A. Whenever the data type might be many bytes.
   • B. Whenever the data type might be many bytes, the function changes the parameter within its body, and you do NOT want these changes to alter the actual argument.
   • C. Whenever the data type might be many bytes, the function changes the parameter within its body, and you DO want these changes to alter the actual argument.
   • D. Whenever the data type might be many bytes, and the function does not change the parameter within its body.

9. Here is a small function definition:

    void f(int i, int &k) { i = 1; k = 2; } 

   Suppose that a main program has two integer variables x and y, which are given the value 0. Then the main program calls f(x,y); What are the values of x and y after the function f finishes?
   • A. Both x and y are still 0.
   • B. x is now 1, but y is still 0.
   • C. x is still 0, but y is now 2.
   • D. x is now 1, and y is now 2.

10. Here is a function prototype and some possible function calls:

     int day_of_week(int year, int month = 1, int day = 1); // Possible function calls: cout << day_of_week( ); cout << day_of_week(1995); cout << day_of_week(1995, 10); cout << day_of_week(1995, 10, 4); 

    How many of the function calls are legal?
    • A. None of them are legal
    • B. 1 of them is legal
    • C. 2 of them are legal
    • D. 3 of them are legal
    • E. All of them are legal

    Multiple Choice Section 2.5 Operator Overloading and Friends

11. Which kind of functions can access private member variables of a class?
    • A. Friend functions of the class
    • B. Private member functions of the class
    • C. Public member functions of the class
    • D. All of the above can access private member variables
    • E. None of the above