Midterm

Question 1

_______ declared _____ are meaningful only within

the file they are declared in

Answer 1

Globals declared static are meaningful only within

the file they are declared in

Question 2

Globals visible in other files by declaring it as _____

Answer 2

extern

Question 3

Global variables are in scope from moment of declaration until ___ ___ ___

Answer 3

end of file (not in-scope earlier in file)

Question 4

a variable defined inside a _____ is
meaningful only inside that function
• It is said to have _____ scope

Answer 4

a variable defined inside a function is
meaningful only inside that function
• It is said to have local scope

Question 5

int count = 0; // Create a global variable

int count_items()
{
	int orig_count = count;

int count = 3;

for (int i = 0; i < 4; ++i)
	count++; 
return count + orig_count; }

what is the output?
int main() 
{ cout << count << endl;
cout << count_items();
}

Answer 5

0

7

Question 6

When an inner variable has the same name as an outer variable, the outer variable is _______ by the inner variable

Answer 6

When an inner variable has the same name as an outer variable, the outer variable is shadowed by the inner variable

Question 7

double balance; // Balance has global scope
class BankAccount
{
public:
BankAccount(double balance);
// Parameter variable balance has local scope
private:
double balance;
// Data field balance has class scope
};

BankAccount::BankAccount(double balance)
{
this->balance = balance;
// Assign \_\_\_\_ \_\_\_\_\_\_ \_\_\_\_\_\_ using parameter
value
\::balance = balance;
// Assign \_\_\_\_\_\_ \_\_\_\_\_\_ using \_\_\_\_\_\_ value
}

Answer 7

double balance; // Balance has global scope
class BankAccount
{
public:
BankAccount(double balance);
// Parameter variable balance has local scope
private:
double balance;
// Data field balance has class scope
};

BankAccount::BankAccount(double balance)
{
this->balance = balance;
// Assign data field balance using parameter
value
\::balance = balance;
// Assign global variable using parameter value
}

Question 8

What is definition of variable scope?

Answer 8

Where a name is visible

Question 9

What is definition of variable lifetime?

Answer 9

How long a variable exists during program execution

Question 10

• A static local variable is allocated and initialized when
the program loads, and exists until _____ _____
• Only visible to __ _______

Answer 10

• A static local variable is allocated and initialized when
the program loads, and exists until program exits.
Only visible to the function

Question 11

What functions can access protected sections of a class?

Answer 11

functions within that class and children of that class

Question 12

How should the protected designation be used?

Answer 12

Same caution as public. Only accessors

Question 13

• It is common to grant friendship to the _____ operators

Answer 13

• It is common to grant friendship to the stream operators

Question 14

Friend functions and classes can access what data of the class friendship is defined in?

Answer 14

Can access all protected and private data

Question 15

Substitution principle: If B inherits from A, then ______

_____________________

Answer 15

Substitution principle: If B inherits from A, then B can be used wherever A is expected

Question 16

How does inheriting privately from a base class work?

Answer 16

The child class can access base class methods only 
internally and member fields do not flow through. The child class objects can not access base class methods.

Question 17

What is the syntax for declaring a namespace?

Answer 17

namespace name_space_name
{
class Example 
   {
   };
}

Question 18

What is the syntax for dumping a namespace into global namespace?

Answer 18

using namespace name_space_name;

Question 19

Namespaces should be short or long and descriptive?

Answer 19

long and descriptive

Question 20

How are namespaces shortened to a manageable length?

Answer 20

Aliasing

nsn = name_space_name;

Question 21

How do you dump an individual name into the namespace. (ex: std::cout)

Answer 21

using std::cout;

Question 22

namespaces should NEVER be used in what type of file?

Answer 22

header (included) files because the user does not necessarily know what namespace they are dumping into their global namespace and name ambiguities can occur.

Question 23

A destructor is automatically invoked when ______ ______ _________

Answer 23

A destructor is automatically invoked when a class
variable is no longer in scope.

Question 24

Two syntexes for calling copy constructor

Answer 24

String first("Fred");
String second(first);

String second = first;

Question 25

If the user does not write a copy constructor, do copy constructors exist?

Answer 25

Yes the compiler automatically creates one however it uses memberwise copying

Question 26

What is the problem with the constructor provided by the compiler?

Answer 26

Creates only shallow memberwise copying. Problem when copying pointers

Question 27

What is the syntax of a copy constructor?

Answer 27

String::String(const String& right) {}

Question 28

What are the three things that an assignment operator must do?

Answer 28

Check for self assignment
Clean up existing resources
Create a copy of values in rhs

Question 29

What are the 8 instances when a destructor is called?

Answer 29

• Local variables, at end of block
• Parameters, at end of function
• Temporary variables, at end of statement
• Heap values, when delete is called
• Static values, when main terminates
• Member data, when object is deallocated
• Base class object, when derived class object is deallocated
• Local variables, when an exception is thrown and execution
  leaves the block

Question 30

What are the six memory management functions?

Answer 30

1.Copy constructor
2.Assignment operator
3. Destructor
4.Default Constructor
5.Move Constructor (faster than a copy constructor because it
doesn’t allocate memory nor does it copy memory buffers).
6.Move Assignment operator

Question 31

What is the assignment operator syntax?

Answer 31

&Example Example::operator=(const Example& rhs) {}

Question 32

What would happen if you supplied a destructor but no constructor? And one shallow copy of an object went out of scope before the original or vise versa?

Answer 32

The destructor would be called to reallocate resources and an error would emerge if the object was used because it referenced resources that are no longer allocated

Question 33

Each parameter must be preceded by the keyword _____ or ______

Answer 33

Each parameter must be preceded by the keyword class or typename

Question 34

double e = max(2, 3.13)

Answer 34

Why isn’t this allowed? How can it be fixed?

double e = max(2, 3.13);

Question 35

What is the template statement above this class definition?
class Pair
 { public:    
Pair(const F& a, const S& b);   
 F get_first() const;   
 S get_second() const; 
private:    
F first;    
S second; };

Answer 35

template

Question 36

What are the four conditions for when paint event is called?

Answer 36

1. The widget is shown for the first time.
2. The widget is resized.
3. The widget is obscured by another window, and then is revealed again.
4. We force it by a call to repaint() or update().

Question 37

Write an int main for a qapp

Answer 37

#include 
#include 

int main(argc, *argv[])
{
QApplication(argc, argv);
MainWindow w;
w.show();  

return app.exec();
}