Class Quiz

CMPT 135

Spring 2019

What is the difference between a struct and a

class?

a) nothing: they are completely the same

b) a struct cannot have methods

c) a struct cannot have a private part

d) a struct is public by default, and a class is private by default

e) none of the above

What is the name of the pointer that C++ adds

to each object that points to the object itself?

a) this

b) that

c) self

d) whatever the name of the class is

Which one of the these is true of the code on

the right?

a) B is derived from A

b) B inherits from A

c) B is a subclass of A

d) A is a superclass of B

e) all of the above

f) a), b) and c) only

class A {

// …

};

class B : public A {

// …

};

What is the name for a destructor in a class

called File?

a) File

b) ~File

c) delete

d) destroy

e) none of the above

When is a destructor called?

a) whenever the programmer calls it

b) when the object it’s part of is deleted

c) both a) and b)

d) none of the above

What does “= 0” a the end of a method mean?

a) the method cannot be implemented by any method, even in inheriting

classes

b) the method has no implementation in this class

c) it returns 0 by default

d) none of the above

What is a virtual method?

a) an unimplemented method

b) a method that does not change the state of its object

c) a method that can be re-implemented in an inheriting class

d) none of the above

What is an abstract base class?

a) a class where the methods are virtual and “= 0”

b) a class where the methods are virtual, but not necessarily “= 0”

c) a class with no methods

d) a class with no constructors

Which one of the following is true?

a) abstract base classes should never declare a virtual destructor

b) abstract base classes should always declare a virtual destructor

c) destructors are virtual by default

d) destructors cannot be declared virtual

What is a const method?

a) a method that cannot be over-ridden by a method in an inheriting class

b) a method that returns a constant value

c) a method that does not change the state of its object

d) none of the above

Which one of the following is true?

a) both getters and setters should be declared const

b) getters should be declared const

c) setters should be declared const

d) neither setters nor getters should be declared const

Which one of the following is true?

a) a class can inherit from at most one other class

b) a class must inherit from exactly one other class

c) a class can inherit from more than one other class

d) none of the above are true

Thanks for playing!