Part 3 - Control Structures, Operators, Classes and Objects

Question 1

What 3 types of control structures exist?

Answer 1

Selection: if, else, switch

Repetition: while, do, for

Exception: try/catch

Question 2

What is the difference between break and continue?

Answer 2

break will take you completely out of the loop

continue will start the next iteration of the loop

Question 3

What does declaring a function inline do?

Answer 3

Causes a copy of the code to be inserted into the code generated by the compiler instead of a function call

Question 4

If a function is a member of a class it must be applied to _________________ unless it is defined as static

Answer 4

An object of that class

Question 5

How can one give the value 5 a leading 0 when outputting?

Answer 5

cout << setfill(‘0’) << setw(2) << val << endl;

Question 6

What does setw do?

Answer 6

Sets the field width of the next item to be output

Question 7

What does setfill do?

Answer 7

Sets the fill character to be used for all subsequent outputs

Question 8

What 3 visibility specifiers exist in C++?

Answer 8

public

private

protected

Question 9

What is private visibility?

Answer 9

Private members can only be accesses in functions of the class and its friend functions

Question 10

What is protected visibility?

Answer 10

Protected members can only be accessed in functions and friend functions of the class or subclasses of the class

Question 11

What is public visibility?

Answer 11

Public members can be accessed anywhere in the program as long as the class is in scope

Question 12

What is the default visibility level?

Answer 12

Private

Question 13

If no constructor is provided for a class the compiler will generate a __________

Answer 13

No argument constructor

Question 14

What does a default no argument constructor do?

Answer 14

Calls the no argument constructors of any members of the class that are class objects

Will NOT initialise any primitive objects

Question 15

Where should default parameters for constructors be specified?

Answer 15

In the constructor definition in the header file

Question 16

How would you create a new object of type Time on the heap?

Answer 16

Time *tPtr1 = new Time;

Question 17

If a class object has been declared constant, e.g.

const Time noon(12);

The only functions that can be applied to the object are _________________

Answer 17

Constant member functions

Question 18

Where must initialisation of non static class members be performed?

Answer 18

In the constructor(s) of the class

Question 19

What is an initialiser list?

Give an exame using the Time class

Answer 19

A way to initialise members outside the constructor

Time::Time() : hour(0), sec(0), min(0) {

//…

}

Question 20

How should members of a class, that are themselves objects of a type of class, be initialised?

Demonstrate with this class:

class Lecture {

private: Time startTime;
public: Lecture(….., int startHour);

};

Answer 20

Initialiser lists

Lecture::Lecture(….., startHour) : startTime(startHour) { … }

Question 21

If a class has as a member an object of another class and has a constructor in which that member is not initialised, what happens?

Answer 21

The no argument constructor for the class is invoked.

Question 22

If any object member belongs to a class that has no no-argument constructor, what cannot be used? Hence, what must we provide?

Answer 22

Default no-arg constructor

A constructor that initialises the object in its initialiser list

Question 23

When must a non constant static class member be initialised?

Answer 23

Outside of any declaration, i.e. perhaps at the top of the cpp file

Question 24

For the class:

class Employee {

private:

int payRollNum;

static int count;

public:

Employee();

};

Demonstrate how count would be initialised

Answer 24

// Employee.cpp

Employee::count = 0;

Employee::Employee() {…}

Question 25

What does this refer to in a function?

Answer 25

A pointer to the instance of the object

Question 26

How can a reference to the current object be retrieved?

Answer 26

*this