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Learn Object-Oriented Programming in C++ Educative Quiz Answers
Get Learn Object-Oriented Programming in C++ Educative Quiz Answers
Object-oriented programming (OOP) has been around for decades. If you have a basic understanding of C++ and are interested in leveling up your skills, this class will help you do just that.
Starting with an overview of the basics, you’ll dive into understanding the time-honored technique for implementing complex applications using user-defined classes. Followed up by discussing classes and objects, and then building up to the high-level topics including inheritance and polymorphism.
Throughout the course, you’ll be fully immersed in OOP for C++, with illustrations, exercises, quizzes, and hands-on challenges every step of the way. You’ll walk away with an understanding of classes and objects behavior and be able to easily create simple, efficient, reusable and secure code.
Quiz 1: Introduction
Q1. Which of the following represents correct syntax of a function call in C++?
- func_call( parameter1 = 5, parameter2 = 10 );
- func_call( parameter1, parameter2 );
- func_call( parameter1; parameter2 );
Q2. The following declaration of an integer array is best explained by which of the given statement?
int arr[4][3];- It is an integer array with 4x3x2 bits of memory
- It is an integer array with 4x3x4 bits of memory
- It is an integer array with 4x3x4 bytes of memory
Q3. A static integer array is a constant pointer in C++. Which of the following is the correct explanation of this statement?
- Because its data is fixed and cannot be changed throughout the program
- Because it has to be initialized at the time of declaration
- Because the memory the array points to is fixed and cannot be changed
Q4. What is the difference between a reference variable and a pointer in C++?
- A pointer stores the address of the variable whereas a reference variable is just an alias for that variable
- A pointer and reference variable have no difference
- A reference variable has a smaller scope than a pointer
Q5. The following line of the code will generate a syntax error because:
static int temp;- There is no keyword static in C++
- A static variable has to be initialized at the time of declaration
- In C++, only functions can be static
Quiz 2: Functions
Q1. The declaration of a function consists of the following parts:
- Function name
Arguments - Function name
Arguments
Return type - Function name
Definition code - Return type
Function name
Q2. The definition of a function is contained inside:
{ }curly brackets[ ]squared brackets( )parentheses
Q3. What is the output of the following program?
void square(int num){
num = num * num;
return num;
}
int main(){
int x = 5;
square(5);
cout << x << endl;
}- 25
- 5
- Compilation error
Q4. A variable declared inside a function cannot be used outside the function’s scope.
- True
- False
Q5. What is the output of the follow code?
bool foo(int n){
if(n > 20){
return true;
}
else{
return false;
}
}
int main(){
bool b;
b = foo(20);
cout << b;
}- True
- False
- Compilation error
Challenge 1: Sum of All Odd Integers in an Array
Answer:
int sumAllOdds(int arr[], int size) {
int sum = 0;
for(int i = 0 ; i < size; i++) {
if(arr[i] % 2 != 0) { // checks if number is odd
sum += arr[i];
}
}
return sum;
}Challenge 2: Find the Second Minimum in an Array
Answer:
int secondMinimum(int arr[], int size) {
int min = 214748364;
int secondmin = 214748364;
for (int i = 0; i < size; i++) {
if (arr[i] < min) {
secondmin = min;
min = arr[i];
}
else if (arr[i] < secondmin) {
secondmin = arr[i];
}
}
return secondmin;
}Challenge 3: Square Numbers and Return their Sum
Answer:
float squareSum(float num1, float num2, float num3) {
float sum = 0;
num1 = num1 * num1;
num2 = num2 * num2;
num3 = num3 * num3;
sum = num1 + num2 + num3;
return sum;
}Challenge 4: Overload the Square Sum Function
Answer:
int squareSum(int num1, int num2, int num3) {
int sum = 0;
num1 = num1 * num1;
num2 = num2 * num2;
num3 = num3 * num3;
sum = num1 + num2 + num3;
return sum;
}Quiz 3: Pointers
Q1. Which operator can be used to dereference a pointer, p?
- =
- *
- >>
- <<
Q2. Pointers allows us to point to objects in:
- The heap
- The stack
- Both
Q3. What will be the value of *p at the end of this code?
int *p;
int var = 10;
p = &var;
*p = 15;
var = 20;- 10
- 15
- 20
Q4. What will be the value of *x and y after the foo function call in the code below?
void foo(int *p, int q){
*p = *p + q;
q = *p * q;
}
int main(){
int *x = new int(5);
int y = 7;
foo(x, y);
}- x = 12
y = 35 - x = 12
y = 7 - x = 5
y = 35 - x = 5
y = 7
Q5. What command can be used to free dynamic memory reserved by a pointer?
- delete
- remove
- free
Challenge 5: Halving a Number
Answer:
void halve(double* n){
*n = *n/2;
}Challenge 6: Swap Values
Answer:
void swapVals(int *p, int *q){
int temp = *p;
*p = *q;
*q = temp;
}Quiz 4: Classes
Q1. The attributes of a class can be divided into the following two parts:
- Data pointers and member functions
- Data members and data pointers
- Member functions and data members
- None of the above
Q2. What is the output of the code below?
class Score {
int num;
public:
Score(){
num = 0;
}
Score(int n){
num = n;
}
int getNum(){
return num;
}
};
int main() {
Score sc(5);
cout << sc.num;
}- 5
- 0
- Compile error
- Runtime error
Q3. The scope resolution operator can be used to define member functions outside the class definition in the following syntax:
returntype memberFunction::className- True
- False
Q4. Data members are usually kept:
- Private
- Public
- Does not matter
Q5. Member functions are usually kept:
- Private
- Public
- Does not matter
Challenge 7: Calculating Perimeter and Area of a Rectangle
Answer:
class Rectangle {
public:
float length, height;
Rectangle(float l, float h) {
length = l;
height = h;
}
float perimeter() {
return length*2 + height*2;
}
float area() {
return length*height;
}
};Challenge 8: Calculate Student’s Total Marks
Answer:
class Student
{
private:
float mark1;
float mark2;
string name;
public:
// Constructor with no arguments (default constructor)
Student() {
name = "";
mark1=0;
mark2=0;
}
// Constructor with three arguments
Student(string na, float ma1,float ma2) {
name=na;
mark1=ma1;
mark2=ma2;
}
int GetMarks(int marknumber) {
if(marknumber == 1){
return mark1;
}
else{
return mark2;
}
}
float calc_total() {
return (mark1+mark2);
}
};
Challenge 9: Implement a Calculator Class
Answer:
class calculator{
float num1, num2;
public:
calculator() {
num1 = 0;
num2 = 0;
}
int add(float n1, float n2){
num1 = n1;
num2 = n2;
return num1 + num2;
}
float subtract(float n1, float n2){
num1 = n1;
num2 = n2;
return num2 - num1;
}
float multiply(float n1, float n2){
num1 = n1;
num2 = n2;
return num1 * num2;
}
float divide(float n1, float n2){
num1 = n1;
num2 = n2;
return num2 / num1;
}
};Challenge 10: Calculate Distance Between Points
Answer:
#include <iostream>
#include <cmath>
using namespace std;
class Point {
// Private fields
private:
int x;
int y;
public:
// Default Constructor
Point() {
x = 0;
y = 0;
}
// Parameterized Constructor
Point(int x, int y) {
this->x = x;
this->y = y;
}
double distance() {
double distance = sqrt(x*x + y*y);
return distance;
}
double distance(int x2, int y2) {
double distance = sqrt(((x2-x)*(x2-x))+((y2-y)*(y2-y)));
return distance;
}
};OOP in C++ Exam 1:
Q1. ______ is a set of statements that performs operations in a program.
- An array
- A variable
- A function
- A class
Q2. What will be the output of the following code?
#include <iostream>
using namespace std;
int add(int a, int b)
{
return (a + b);
}
float add(float a, float b)
{
return (a + (-b));
}
int main()
{
int x1 = 2, y1 = 2;
float x2 = 4.0, y2 = 3.0;
cout << add(x1, y1)<< endl;
cout << add(x2, y2);
return 0;
}- 4 7
- 0 1
- 4 1
- compile-time error
Q3. How will you declare a pointer that holds an integer type?
- int *p
- int &p
- int p
- int p[]
Q4. What is the correct syntax for de-allocating the following array?
int *arr = new int[100];Q5. What will be the output of the following code?
#include <iostream>
using namespace std;
int main()
{
int arr[] = { 5, 10, 8, 4 };
int* p = (arr + 1);
cout << *p + 2 <<endl;
cout << *arr + 10;
return 0;
}- 8 15
- 12 15
- 7 20
- 6 20
Q6. How many access modifiers are present in class?
- 1
- 2
- 3
- 4
Q7. What will happen when you run the following code?
class ExmpClass {
public:
int x;
private:
int y;
};
int main() {
ExmpClass obj;
obj.x = 25;
obj.y = 50;
}- The values of x and y will be set to 25 and 50
- The value of y will be set to 50 but the value of x won’t be set
- An error will occur because y is a private variable that can’t be accessed directly outside of the class
- An error will occur because x can’t be accessed directly outside of the class
Q8. What will be the output of the following C++ code?
#include <iostream>
using namespace std;
class Rectangle
{
int length, width;
public:
Rectangle(){
length = 0;
width = 0;
}
Rectangle(int l, int w){
length = l;
width = w;
}
int area ()
{
return (length * width);
}
};
int main ()
{
Rectangle rectangle(3,4);
rectangle.area();
cout << rectangle.area();
return 0;
}- 0
- 12
- 3
- Error
Q9. Which of the following statements are wrong about a friend function of a class?
- Friend functions are members of a class
- A friend function is an independent function which has access to the variables and methods of its befriended class
- To create a friend function for a class, it must be declared outside the class along with the friend keyword
- Both A & C
Q10. An object is an entity with some data and operations.
- True
- False
Q11. Pass-by-Value method passes the address of a variable as an argument instead of the variable itself.
- True
- False
Q12. The output of the code below will be 8.
#include <iostream>
using namespace std;
void cube(int *a){
if(a != NULL){
*a = (*a) * (*a) * (*a);
}
}
int main() {
int *p = new int(2);
cube(p);
cout << *p;
}
- True
- False
Q13. A C++ class holds only member functions.
- True
- False
Q14. Match the terms in the left column with their respective definitions on the right side:
- destructor
- friend function
- constructor
- Passing-by-reference
- Pass-by-value
- passing the address of a variable as an argument instead of the variable itself.
- is used to construct the object of a class
- passing the values of the arguments into the functions, not the arguments themselves.
- is called when an object of a class is no longer in use
- an independant function which has access to the variables and the methods to its befriended class
Answers:
- destructor –
- friend function –
- constructor –
- Passing-by-reference –
- Pass-by-value –
Q15. In this challenge, you need to write a function isPrime that takes an integer as an argument and displays whether it’s prime or not. It should display yes if the number is prime and no otherwise.
Note: Remember a positive integer which is only divisible by 1 and itself is known as prime number. 0 and 1 are not prime numbers!
Sample input
isPrime(10)
isPrime(3)Sample output
no
yesAnswer:
Q16. In this coding challenge, you need to define a Circle class that has an int type variable radius, a default constructor that initializes the radius to 0, another constructor that initializes the value of radius to a given a value that it takes as an argument, and one member function print_area that prints the area of the circle.
Sample input
If a circle object with a radius of 2 is created and the function print_area is called:
Circle obj(2);
obj.print_area();Sample output
Then it should print the circle’s area which in this case would be 12.57.
12.57Note: You can consider the value of pi to be 3.14.
Answer:
Quiz 5: Data Hiding
Q1. What are the two main components of data hiding?
- Encapsulation and Functions
- Encapsulation and Abstraction
- Abstraction and Implementation
Q2. A header file contains:
- The declaration of the class and its members.
- The implementation of the class and its members
- The main function which executes the program
Q3. The point of data hiding is to reveal the relevant functions needed to interact with a class and keeping the inner implementation hidden.
- True
- False
Q4. Apart from header files, abstraction can be implemented using:
- Functions
- Templates
- Classes
Q5. According to the conventions of data hiding, class member should be:
- Public
- Private
- Public or private
Quiz 6: Inheritance
Q1. What will be the output of following piece of code?
class Base {
public:
Base(){
cout << "Base constructor!" << endl;
}
};
class Derived: public Base {
public:
Derived(){
cout << "Derived constructor!" << endl;
}
};
int main(){
Derived d;
}
- Derived constructor!
- Derived constructor!
Base constructor! - Base constructor!
Derived constructor! - None of the above
Q2. Figure out the sequence in which destructors will be called:
class Base {
public:
~Base() {
cout << " Base destructor!" << endl;
}
};
class Derived: public Base {
public:
~Derived() {
cout << " Derived destructor!" << endl;
}
};
int main() {
Derived d;
}
- Derived destructor!
Base destructor! - Base destructor!
Derived destructor! - Compile Time Error
- Run Time Error
Q3. What is the output of the following code?
class grandParent{
public:
void GPprint() {
cout << "Grandparent print" << endl;
}
};
class Parent: public grandParent {
public:
void Pprint() {
cout << "Parent print" << endl;
GPprint();
}
};
class Child : public Parent {
public:
void Cprint() {
cout << "Child print" << endl;
Pprint();
}
};
int main() {
Child c;
c.Cprint();
}
- Child print
- Grandparent print
Parent print
Child print - Child print
Parent print
Grandparent print - None of the above
Q4. What will the following program display?
#include <iostream>
using namespace std;
class B {
public:
void disp() {
cout << "B";
}
};
class D : public B {
public:
void disp() {
cout << "D";
}
};
class DD : public D {
};
int main() {
DD dd;
dd.disp();
return 0;
}- B
- D
- BD
- DB
- The program wouldn’t compile
Q5. What will be displayed by the following program when it is run?
#include <iostream>
using namespace std;
class B {
private:
int count = 0;
public:
void inc() {
cout << count++;
}
};
class D : public B {
public:
void inc() {
cout << count++;
}
};
int main() {
D d;
d.inc();
return 0;
}- 0
- 1
- 11
- 2
- The program wouldn’t compile
Q6. What will be the output of the following program?
#include <iostream>
using namespace std;
class B {
public:
void greet(int c) {
cout << c;
}
void greet() {
cout << "Hello B";
}
};
class D : public B {
public:
void greet() {
cout << "Hello D";
}
};
int main() {
D d;
d.greet(3);
return 0;
}- Hello B
- Hello D
- Hello BHello D
- Hello DHello B
- The program wouldn’t compile
Q7. What will be the output of the following program?
#include<iostream>
using namespace std;
class B
{
protected:
int count;
public:
B() {count = 0;}
};
class D1: public B
{
public:
int sep;
};
class D2: public B
{
public:
int set;
};
class DD: public D1, public D2
{
public:
void show() { cout << count; }
};
int main(void)
{
DD d;
d.show();
return 0;
}- 0
- 1
- The program wouldn’t compile
Q8. What will be the output of the following program?
#include<iostream>
using namespace std;
class B
{
protected:
int count;
public:
B() {count = 0;}
int getCount() { return count; }
};
class D : protected B
{
public:
void disp() { cout << getCount(); }
};
int main(void)
{
D d;
d.disp();
return 0;
}- 0
- The program wouldn’t compile
Q9. What will be the output of the following program?
#include<iostream>
using namespace std;
class B
{
private:
const int ID = 10;
protected:
int count;
public:
B() {count = 0;}
int getCount() { return count; }
};
class D : protected B
{
public:
void disp() { cout << getCount(); }
int getID() { return ID; }
};
int main(void)
{
D d;
d.getID();
return 0;
}- 10
- The program wouldn’t compile
Q10. What will be the output of the following program?
#include<iostream>
using namespace std;
class B
{
private:
const int ID = 10;
protected:
int count;
public:
B() {count = 0;}
int getCount() { return count; }
};
class D : private B
{
public:
void disp() { cout << getCount(); }
int getID() { return ID; }
};
int main(void)
{
D d;
d.getID();
return 0;
}- 10
- The program wouldn’t compile
Challenge 11: Implement the Derived Class
Answer:
// Derived Class
class Car : public Vehicle {
string name; // Name of a Car
public:
Car() { // Default Constructor
name = "";
}
// This function sets the name of the car
void setDetails(string name) { // Setter Function
this->name = name;
}
// This function calls the Base class functions and appends the result with the input
string getDetails(string carName) {
string details = carName + ", " + getModel() + ", " + getSpeed(); // calling Base Class Function
return details;
}
};Quiz 7: Polymorphism
Q1. What is the output of the following piece of code?
#include <iostream>
using namespace std;
class Base{
public:
virtual void print() {
cout <<" Base Print";
}
};
class Derived: public Base{
public:
void print() {
cout <<"Derived Print" ;
}
};
int main(){
Base * bp;
Derived obj;
bp = &obj;
bp->print();
}- Derived Print
Base Print
- Base Print
- Derived Print
- None of the above
Q2. Does the code run successfully?
#include<iostream>
using namespace std;
class Base{
public:
virtual void show() = 0;
};
int main(){
Base b;
Base *bp;
}- Yes
- No
Q3. What does the following piece of code do?
#include <iostream>
using namespace std;
class Shape {
public:
virtual float getArea() = 0;
};
class Rectangle : public Shape {
private:
float width;
float height;
public:
Rectangle(float wid, float heigh) {
width = wid;
height = heigh;
}
float getArea(){
return width * height;
}
};
int main() {
Shape * shp = new Rectangle(4, 5);
float num = shp->getArea();
cout << "Area of rectagle is " << num << endl;
}- Area of rectagle is 20
- Compile time error
- Run time error
- None of the above
Quiz 8: Composition, Aggregation and Association
Q1. In a part-of relationship between two classes:
- Both classes must be a part of the other
- One class must be a part of the other.
- Both classes should be parts of a third class
Q2. What kind of relationship does composition use?
- Part-of
- Has-A
- None of the above
Q3. In aggregation, a class can reference the object of another class using:
- Functions
- Variables
- Pointers
- Inheritance
Q4. Two associated classes cannot exist independently.
- True
- False
Q5. What kind of relationship does association follow?
- Part-of
- Has-a
- None of the above
OOP in C++ Exam 2:
Q1. Which option correctly describes encapsulation?
- concept of hiding the workings of a class and not letting the outside world interact with it
- combining data members and functions in a single class preventing access to the data directly, instead providing it through the functions of the class
- concept of combining various member functions into a single unit
- concept of combining data members into a single unit
Q2. Which option correctly describes abstraction?
- Revealing the implementation and the relevant parts of the application
- Revealing only the relevant parts of the application while keeping the inner implementation hidden
- Hiding the important data
- Hiding the important features of the application
Q3. What will be the output of the following code?
#include <iostream>
using namespace std;
class A {
public:
void print() { cout <<"Inside A"; }
};
class B : public A {
public:
void print() { cout <<"Inside B"; }
};
class C: public B { };
int main()
{
C c;
c.print();
return 0;
}- Inside A Inside B
- Inside B Inside A
- Inside A
- Inside B
Q4. What will be the output of the following code?
#include <iostream>
using namespace std;
class A {
public:
A(){
cout << "A's constructor called" << endl;
}
~A() { cout << "A's destructor called" << endl; }
};
class B : public A {
public:
B(){
cout << "B's constructor called" << endl;
}
~B() { cout << "B's destructor called" << endl; }
};
int main() {
B b;
return 0;
}
- B’s constructor called B’s destructor called
- A’s constructor called A’s destructor called
- B’s constructor called A’s constructor called A’s destructor called B’s destructor called
- A’s constructor called B’s constructor called B’s destructor called A’s destructor called
Q5. ____________ members of base class are inaccessible to the derived class.
- Public
- Private
- Protected
- Public and private
Q6. What will be the output of the following code?
#include <iostream>
using namespace std;
class Shape {
public:
float getArea(){}
};
class Square : public Shape {
private:
float width;
float length;
public:
Square(float w, float l) {
width = w;
length = l;
}
float getArea(){
return width * length;
}
};
int main() {
Square sq(2, 6);
Shape* shape = &sq;
cout << sq.getArea() << endl;
cout << shape->getArea() << endl <<endl;
}
- 12 0
- 0 12
- 12 12
- 0 0
Q7. What will be the output of the following code?
#include<iostream>
using namespace std;
class A
{
public:
virtual void show() { cout<<"In A"<<endl; }
};
class B: public A
{
public:
void show() { cout<<"In B"<<endl; }
};
class C: public B
{
public:
void show() { cout<<"In C"<<endl; }
};
int main(void)
{
B b;
A* a = &b;
a->show();
C c;
a = &c;
a->show();
return 0;
}
- In A In B In C
- In B In C
- In A In B
- In A In C
Q8. What type of relationship (composition, aggregation, or association) does the following describe?
A House class that contains member objects of type Door, Window, and Wood class.
- Composition
- Aggregation
- Association
- None of the above
Q9. What type of relationship (composition, aggregation, or association) does the following describe?
A dance class led by a teacher, and the students can join or drop out of it.
- Composition
- Aggregation
- Association
- None of the above
Q10. Encapsulation makes classes easier to change and maintain as well as provides more flexibility as we decide which variables have read/write privileges.
- True
- False
Q11. The advantages of inheritance include data hiding, avoiding code duplication, and extensibility.
- True
- False
Q12. Overriding needs inheritance, however, the function in derived class/es should not have the same declaration as the function as of the base class.
- True
- False
Q13. In aggregation, the lifetime of the owned object does not depend on the lifetime of the owner.
- True
- False
Q14. Match the terms in the left column with their respective definitions on the right side:
- Overloading
- Multiple Inheritance
- Multilevel Inheritance
- Pure Virtual Function
- inheriting multiple classes as base classes
- making a function perform different operations based on the nature of its arguments
- function with the expression =0 added to the declaration
- inheriting data members and member functions of a base class which is already inherited from another class
Answers:
- Overloading –
- Multiple Inheritance –
- Multilevel Inheritance –
- Pure Virtual Function –
Q15. In this challenge, you need to define a class Average. It should contain the data members num1, num2, and num3 of type int. Next, you need to define a constructor that initializes these numbers with the values it takes as arguments. You also need to define a function print_average that prints the average of the three numbers.
Sample input
Average obj(1,2,3);
obj.print_average();Sample output
2Answer:
Q16. In this challenge, you have to implement inheritance between the classes Shape and Square. The Shape class has a private member color. You need to define the setColor and getColor functions to be able to access this private member.
The Square class derives from Shape. It has the length and width data members. You need to initialize the constructor and define the following two functions:
display_area: calculates and displays the area of the squaredisplayColor: displays the color of the square
Hint: You can access the
getColorfunction in theSquareclass as it derives from theShapeclass.
Sample input
Square sq(4,3);
sq.setColor("red");
sq.display_area();
sq.displayColor();Sample output
"The area of the square is: 12"
"The color of the square is: red"Answer:
Conclusion:
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