Deck 7: Constructors and Other Tools

Question 1

A constructor is like a function.It can return any type value needed.

Answer 1

False

Question 2

A constructor is a special kind of member function.It is automatically called when an object of that class is declared.

Answer 2

True

Question 3

A constructor usually terminates by falling off the end of its block,but a return statement is permitted if there is no argument add following the word return..

Answer 3

True

Question 4

Assignment behaves essentially the same for vectors as for arrays.

Question 5

A local class and a nested class are the same thing.

Question 6

If v is a vector and i is an int variable,then in the following the value of i can be any nonnegative int value:
v[i] = i;

Question 7

The set of integers ranging from -MAXINT to MAXINT make up the int data type.

Question 8

A class may not have another class type object as a member.

Question 9

A constructor is always named construct with class name attached.If the class is Foo,then the constructor name is constructFoo.

Question 10

It is valid to initialize member variables in a class on the same line in which the variable is declared.For example,the following sets xx to 1000:
class A
{
public:
A(){}
private:
int xx = 1000;
};

Question 11

A static variable of a class cannot be changed.

Question 12

The keyword static is used in a static function declaration in a class but not in the function definition.

Question 13

size and capacity of a vector are two names for the same thing.

Question 14

The functions or data members declared in the private: section of a class can be accessed only in the definition those functions declared in that class.Note that friend functions are also declared (but not defined)in the class to which they are friends,so they also have access to private as well as public members.

Question 15

Any use of the keyword const is a promise to the compiler,and a request to the compiler to enforce the promise.What promises?

Question 16

Vector assignment is well behaved.

Question 17

You can write a class that is useful with all its constructors in the private section.

Question 18

A constructor can be called implicitly or explicitly.(Implicitly means the compiler did it for you. )In the interest of uniformity in answers,please use class A;for your examples.

Question 19

Inline functions are always more efficent than noninline functions.

Question 20

It is legal to call a constructor as a member function of an object of a class,as in
class A
{
public:
A(){}
A(int x,int y):xx(x),yy(y){}
// other members
private:
int xx;
int yy;
};
int main()
{
A w;
w.A(2,3);// Is this legal?
}

Question 21

Which of the following are legal access to the class or struct members? Assume each is outside of the class member definitions,
struct S class C class D
{ { {
int x;int x;public:
int y;int y;int x;
} private: int y;
S s;int z;private:
};int z;
C c;};
D d;
a)s.x
b)c.x
c)d.x
d)c.z
e)d.z

Question 22

Describe the differences between a call to an inline function member and a function that is not declared inline..What advantages are there to inline? What disadvantages?

Question 23

A constructor

A)can only be used to initialize
B)must initialize all member variables
C)can do anything any other method can do.
D)usually initializes all,or most,member variables

Question 24

Describe in terms of who needs access to class members why the public members should come first in a class definition.

Question 25

Given the definitions below.Rewrite the definition of this class so that functions f()const and g(const A& x)are inline.
const int x = 17;
class A
{
public:
A( );
A(int n);
int f( )const;
int g(const A& x);
private:
int i;
};

Question 26

Suppose you have a class whose objects are very,very large.Briefly,describe the advantages and drawbacks of call-by-value and call-by-reference for large objects.Describe a parameter passing mechanism that will allow the safety of call-by-value and the efficiency of call-by-reference.

Question 27

Explain why data members,in particular should be placed in the private section of a class.

Question 28

Which of the following are accurate comparisons between call-by-value and const call-by-reference?

A)Both protect against changing the caller's argument.
B)Both are very fast for all sizes of objects.
C)Call-by-value copies the argument whereas const call-by-reference does not
D)Call by value uses more memory than const call-by-reference in making the copy.

Question 29

A class member that is to be shared among all objects of a class is called

A)A const member
B)A reference member
C)A static member.
D)A value member
E)A function member

Question 30

Why is it an error to add a const modifier,as shown to the declaration for the member function input given here?
class BankAccount
{
public:
void input( )const;
// other members
};

Question 31

What is a default constructor? When does a class not have a default constructor?

Question 32

If we use an out of range index with a vector,there be an error message from the compiler.