Deck 11: Friends, Overloaded Operators, and Arrays in Classes

Question 1

Operators must be friends of the class.

Answer 1

False

Question 2

Friend functions may directly modify or access the private data members.

Answer 2

True

Question 3

Functions that are constant member functions may call constant class accessor functions.

Answer 3

True

Question 4

Putting the keyword const after the function declaration guarantees __________________________

Question 5

If you have mutators and accessors, you should not have friend functions also

Question 6

If a given task being performed by a function involves one object, then that function should normally be a __________ function.

Question 7

Functions that are constant member functions may call the class mutator functions.

Question 8

You cannot create new operators such as the quote).

Question 9

In order to do automatic type conversion for your class, you would write _________

Question 10

An operator that expects two parameters is called a ________ operator.

Question 11

An overloaded extraction or insertion operator should return ___________

Question 12

Putting the keyword const in front of a pass by reference parameter guarantees ___________________

Question 13

The following is a properly declared overloaded insertion operator for myClass.
ostream& operator <

Question 14

A friend function needs to be passed an object of the class. If the friend only needs to access the object, but not change its data members, then the object should be passed as _______________

Question 15

You may not change the precedence of operators by overloading them

Question 16

All operators can be overloaded.

Question 17

If a given task being performed by a function involves more than one object, then that function should normally be a __________ function.

Question 18

An operator that expects only one parameter is called a ________ operator

Question 19

A _________ function is not a member of the class, but has access to the private members of the class.

Question 20

Friend functions are members of the class.

Question 21

Write the function declaration for a copy constructor for a class named myClass

Question 22

If c is a character variable that contains a digit, what does the following function return?
Int digit_to_intchar c)
{
Return intc) - int'0'));
}

A) The ASCII value of c
B) The character value of c
C) The integer equivalent of the digit stored in c
D) none of the above

Question 23

Write the function declaration for an assignment operator for a class named myClass

Question 24

Who can access private data in a class?

A) members of the class
B) friends of the class
C) everyone
D) B and C
E) no one

Question 25

Which of the following would be an appropriate function declaration to add two rational numbers?

A) void friend operator+ const Rational &left, const Rational &right);
B) void operatator+ const Rational &left, const Rational &right);
C) friend Rational operator+ const Rational &left, const Rational &right);
D) Rational operator+ const Rational &left, const Rational &right);

Question 26

To overload functions with symbolic names like + - / <<), you must use the keyword _______ before the symbolic name.

A) const
B) operator
C) reference
D) void

Question 27

Operators can be overloaded as

A) friends of a class
B) members of a class
C) non-friends, non-members of a class
D) All of the above

Question 28

Given the following class, which is the correct function header for the display function?
Class Rational
{
Public:
Rational);
Rationalint numer, int denom);
Rationalint whole);
Int getNumerator);
Int getDenominator);
Friend void displayostream& out, const Rational& value);
Private:
Int numerator;
Int denominator;
};

A) friend void displayostream& out, const Rational& value)
B) void displayostream& out, const Rational& value)
C) void Rational::displayostream& out, const Rational& value)
D) friend void Rational::displayostream& out, const Rational& value)

Question 29

The assignment operator must be a _________ of the class.

Question 30

When overloading an operator, which of the following is true?

A) One of the arguments must be an object of the class
B) The operator can be a friend or a member of the class.
C) The operator does not have to be a friend or a member of the class
D) All of the above
E) None of the above

Question 31

How many parameters are there in a binary operator implemented as a friend?

A) 0
B) 1
C) 2
D) as many as you need

Question 32

How many members data and functions) does the following class have?
Class Rational
{
Public:
Rational);
Rationalint numer, int denom);
Rationalint whole);
Int getNumerator);
Int getDenominator);
Friend void displayostream& out, const Rational& value);
Private:
Int numerator;
Int denominator;
};

A) 2
B) 6
C) 5
D) 7
E) 8

Question 33

What is wrong with the following overloaded extraction operator declaration?
Istream& operator >>istream& in, const myClass &object);

A) Object should not be a pass by reference parameter
B) Object should not be a const parameter
C) You can not put the & on the return type
D) nothing

Question 34

Since accessor functions in a class do not modify or mutate the data members of the object, the function should have the __________ modifier.

A) reference
B) friend
C) const
D) private

Question 35

Write the function declaration for a destructor for a class named myClass

Question 36

Both the copy constructor and the assignment operator should make ___________

Question 37

Given the following class, what is syntactically wrong with the implementation of the display function?
Class Rational
{
Public:
Rational);
Rationalint numer, int denom);
Rationalint whole);
Int getNumerator);
Int getDenominator);
Friend void displayostream& out, const Rational& value);
Private:
Int numerator;
Int denominator;
};
Void displayostream& out, const Rational& value)
{
Out << value.getNumerator) << '/"<}

A) nothing
B) value must be not be pass by reference
C) The get functions are not const functions
D) out should be pass by value

Question 38

Why should you generally pass an object of the class to a friend function as a reference parameter?

A) If the friend function changes the values of the data members).
B) If the friend function will not change the values of the data members).
C) It is more efficient to pass the object by reference.
D) A and B
E) A and C

Question 39

How many parameters are there in a unary operator implemented as a friend?

A) 0
B) 1
C) 2
D) as many as you need

Question 40

If we have a full selection of accessor and mutator functions, why would we have friend functions?

A) You should not have them
B) More efficient access to the private data members.
C) The friend function must call the accessor or mutator functions anyway.
D) none of the above

Question 41

What member functions do you need to allow the compiler to perform automatic type conversions from a type different than the class to the class?

A) Overloaded constructors
B) Converters
C) This can not be done
D) This already happens automatically

Question 42

Given the following function declaration,
Friend void displayconst myClass& object);
Which is the correct header for the definition of the function?

A) void myClass::displayconst myClass& object)
B) void displayconst myClass& object)
C) friend void displayconst myClass& object);
D) friend void displayconst myClass& object)

Question 43

The destructor for a class is called

A) explicitly from the main program
B) when the class is instantiated
C) when the object of the class goes out of scope
D) Only at the end of main

Question 44

Which of the following statements are true?

A) A dynamic array can have a base type which is a class or a struct.
B) A class or a struct may have a member which is a dynamic array.
C) A and B
D) Neither

Question 45

In an overloaded insertion or extraction operator, which object should be the first parameter, the stream or the object of the class?

A) the stream
B) the object
C) it doesn't matter
D) none of the above

Question 46

If obj1 and obj2 are both objects of a class that uses dynamic memory allocation, but the class does not have an assignment operator, what happens if you execute the following code?
Obj1=obj2;

A) A syntax error occurs, you can not assign one object to another object without the = operator
B) A run-time error occurs, because the C++ system does not know how to do the assignment.
C) The pointers) to the dynamically declared memory in obj2 are copied to the corresponding pointers in obj1.
D) There is a complete and independent copy of all the dynamic memory from obj2 to obj1

Question 47

Which of the following are not correct?

A) The destructor of a class is not named the same as the name of the class, but preceded with a tilde
B) The destructor of a class is not called when an object of the class goes out of scope
C) The destructor of a class is not a member of the class
D) The destructor of a class is a void function
E) all of the above

Question 48

Which of the following statements are true?

A) Array elements may be user-defined types structs or classes)
B) If a function is expecting a variable of the base type of the array, then you can pass an element of the array to the function.
C) All of the above.
D) None of the above.

Question 49

Which of the following are valid declarations for an assignment operator for a class named myClass?

A) void friend operator = myClass& left, const myClass& source);
B) void operator = myClass& left, const myClass& source);
C) void friend operator = const myClass& source);
D) void operator = const myClass& source);

Question 50

The copy constructor for a class is called

A) when an object of the class is passed by value to a function.
B) when an object of the class is initialized by another object of the class
C) when a function returns an object of the class
D) all of the above

Question 51

Which of the following operators can not be overloaded?

A) =
B) ==
C) .
D) []

Question 52

Given the following class and array declaration, how would you print out the age of the 10^th person in the array?
Class personClass
{
Public:
Void setAgeint newAge);
Void setGender char newGender);
Void setSalaryfloat newSalary);
Int getAge);
Char getGender);
Float getSalary);
Private:
Int age;
Char gender;
Float salary;
};
PersonClass people[100];

A) cout << people[10];
B) cout << people[9];
C) cout << people[9].age;
D) cout << people[9].getAge);

Question 53

Why are the extraction and insertion operators always implemented as friends of the class rather than as members of the class?

A) Because the first parameter must be the stream object.
B) They don't, they could be members
C) Because they return a reference
D) Because the stream is passed by reference.

Question 54

Which of the following function declarations would be correct to overload the multiply operator for the Rational numbers class?

A) friend Rational operator timesconst Rational &left, const Rational &right);
B) Rational operator timesconst Rational &left, const Rational &right);
C) friend Rational operator *const Rational &left, const Rational &right);
D) Rational operator *const Rational &left, const Rational &right);

Question 55

What happens when you define a class that used dynamic memory allocation and define a destructor but no copy constructor?

A) If an object of the class is plugged in for a call-by-value parameter, when the function ends, the parameter's dynamic memory is returned to the freestore at the end of the function execution.
B) When an object that was used as an argument for a call-by-value parameter goes out of scope, it will cause a run-time error.
C) It is possible to modify the values in the argument in the function.
D) All of the above
E) None of the above

Question 56

When a dynamic array with a class for a base type is declared, which constructor is called?

A) the copy constructor
B) the destructor
C) the default constructor
D) an explicit constructor