Deck 8: Operator Overloading,friends,and References

Question 1

You can change the behavior of + for the int type using operator overloading.

Answer 1

False

Question 2

Overloading an operator cannot change the precedence of that operator with respect to other operators.

Answer 2

True

Question 3

When overloading an operator,you can create a new operator different from the more usual operators.

Answer 3

False

Question 4

Overloading a binary operator as a member requires two arguments.

Question 5

A friend function has access only to the private members and member functions of the class (and all objects of that class)of which it is a friend.

Question 6

Overloaded operator <<,when used as an output,returns an ostream& to allow chains of output statements,and similarly the overloaded operator >> returns an istream&

Question 7

Consider this operator overloading for class Money,modified from Display 8.1 by omitting the const modifier on the return type:
Money operator+(const Money& amt1,const Money& amt2);
Is the following expression legal? If legal,what could it mean,and where does the information that is assigned go?
Money m1(17.99),m2(23.57)m3(15,22);
(m1 + m2)= m3;

Question 8

When overloading an operator,you can change the behavior of the operator,making + do things that feel like multiplication,but this is unwise.

Question 9

An overloaded operator[] must be a non-static class member.

Question 10

If a unary operator is overloaded as a stand-alone function,the argument may be any type.

Question 11

An operator overloading is essentially a function that uses a different syntax for invocation.

Question 12

It is impossible to get short-circuit behavior for overloaded operator && or operator ||

Question 13

The operator prefix operator ++ is an l-value,and the text asserts that we should emulate this with operator overloads by returning a reference from prefix versions of operator++.

Question 14

When overloading an operator,you cannot change the number of arguments an operator takes.

Question 15

Overloading a binary operator as a stand-alone function requires two arguments.

Question 16

A class can have friends that are functions as well as friend classes.

Question 17

When an operator is overloaded as a member of a class,the first parameter listed in parentheses,is the calling object.

Question 18

C++ allows overloading of the function application operator ( ).Explain.

Question 19

An overloaded operator= function must be a non-static class member.

Question 20

One can guarantee left to right evaluation of the arguments to a comma expression overloading.

Question 21

Given the class definition:
class A
{
public:
//constructors
// other members
private:
int x;
int y;
};
Give declarations of operator functions for each of the following ways to overload operator + You must state where the declaration goes,whether within the class in the public or private section or outside the class.The operator + may be overloaded
a)as friend function
b)as member function
c)as non-friend,non-member function

Question 22

Why have we not needed to overload the assignment operator so far?

Question 23

Which operators cannot be overloaded?

Question 24

If I need to build an object for return from a function,I can construct that function directly in the return statement.

Question 25

Show how to overload the operators << and >> to create stream output for this class.
Make these functions friends of the class Pair.The expected form of a pair is (2,3)for both input and output.To make this problem manageable,you should only provide to accept and discard the parentheses and comma,but you should not check that these particular characters were typed.Output should be the expected form.
class IntPair
{
int first;
int second;
public:
IntPair(int firstValue,int secondValue);
int getFirst( )const;
int getSecond( )const;
};

Question 26

Which operators can be overloaded only as non-static class members?

Question 27

Explain the similarities and differences between (binary)operators such as +,*,-,/ and a function.

Question 28

What do you need to add to the class definition to overload operator < so that it applies to the type Money from Display 8.1? Given this extract from the class Money from Display 8.1 of the text.
class Money
{
public:
Money( );
// other constructors
// other public members
int getCents( )const;
int getDollars( )const;
private:
int dollars;
int cents;
// other private members
};

Question 29

What are some reasons for using friend operator overloading?

Question 30

What objections to the use of friend functions and classes do some experts give?

Question 31

Consider the class definition:
class IntPair
{
int first;
int second;
public:
IntPair(int firstValue,int secondValue);
// prefix operator++ here
// postfix operator ++ here
int getFirst( )const;
int getSecond( )const;
};
a)Give declarations for prefix and postfix versions of operator++
b)Give definitions for prefix and postfix versions of operator++