CA-402 Object Oriented Concepts Through CPP (BBACA) || Question with answer

CA-402 Object Oriented Concepts Through CPP (BBACA) || Question with answer

 

1. Explain the term Data Abstraction in detail.

 

Humans use abstraction in order to manage complex situations. Objects and processes are reduced to basics and referred to in generic terms. Classes allow more direct use of the results of this type of abstraction in software development. The first step towards solving a problem is analysis. In object-oriented programming, analysis comprises identifying and describing objects and recognizing their mutual relationships. Object descriptions are the building blocks of classes.

In C++, a class is a user-defined type. It contains data members, which describe the properties of the class, and member functions, or methods, which describe the capacities of the objects. Classes are simply patterns used to instantiate, or create, objects of the class type. In other words, an object is a variable of a given class.

 

 

 

2. What are the benefits of OOP?

Moving to the advantages of OOP, we would like to say that there are many as this is one of the core development approaches which is widely accepted. Let’s see what the advantages of OOP are offers to its users.

 

1. Re-usability

It means reusing some facilities rather than building them again and again. This is done with the use of a class. We can use it ‘n’ number of times as per our need.

 

2. Data Redundancy

This is a condition created at the place of data storage (you can say Databases)where the same piece of data is held in two separate places. So the data redundancy is one of the greatest advantages of OOP. If a user wants a similar functionality in multiple classes, he/she can go ahead by writing common class definitions for similar functionalities and inherit them.

 

3. Code Maintenance

This feature is more of a necessity for any programming languages; it helps users from doing re-work in many ways. It is always easy and time-saving to maintain and modify the existing codes by incorporating new changes into them.

 

4. Security

With the use of data hiding and abstraction mechanism, we are filtering out limited data to exposure, which means we are maintaining security and providing necessary data to view.

 

5. Design Benefits

If you are practicing on OOPs, the design benefit a user will get is in terms of designing and fixing things easily and eliminating the risks (if any). Here the Object-Oriented Programs forces the designers to have a long and extensive design phase, which results in better designs and fewer flaws. After a time when the program has reached some critical limits, it is easier to program all the non-OOP’s one separately.

 

6. Better productivity

with the above-mentioned facts of using the application definitely enhances its users overall productivity. This leads to more work done, finishing a better program, having more inbuilt features, and easier reading, writing and maintaining. An OOP programmer cans stitch new software objects to make completely new programs. A good number of libraries with useful functions in abundance make it possible.

 

7. Easy troubleshooting

lets witness some common issues or problems any developers face in their work.

Is this the problem in the widget file?

Is the problem is in the WhaleFlumper?

Will I have to trudge through that ‘sewage.c’ file?

Commenting on all these issues related to code.

So, many times, something has gone wrong, which later becomes so brainstorming for the developers to look where the error is. Relax! Working with OOP language, you will know where to look for. This is the advantage of using encapsulation in OOP; all the objects are self-constrained. With this modality behavior, the IT teams get a lot of work benefits as they are now capable of working on multiple projects simultaneously with an advantage that there is no possibility of code duplicity.

 

8. Polymorphism Flexibility

Let’s see a scenario to better explain this behavior.

You behave in a different way if the place or surrounding gets change. A person will behave like a customer if he is in a market, the same person will behave like a student if he is in a school and as a son/daughter if put in a house. Here we can see that the same person showing different behavior every time the surroundings are changed. This means polymorphism is flexible and helps developers in a number of ways.

It’s simplicity

Extensibility

 

9. Problems solving

Decomposing a complex problem into smaller chunks or discrete components is a good practice. OOP is specialized in this behavior, as it breaks down your software code into bite-sized – one object at a time. The broken components can be reused in solutions to different other problems (both less and more complex), or either they can be replaced by the future modules that relate to the same interface with implementations details.

 

 

 

 

 

3. Explain the following terms:

(a) Object

Object -- an encapsulation of data along with functions that act upon that data.

An object consists of:

 

Name -- the variable name we give it

Member data -- the data that describes the object

Member functions -- behavior aspects of the object (functions related to the object itself)

 

(b) Class.

Class -- a blueprint for objects. A class is a user-defined type that describes what a certain type of object will look like. A class description consists of a declaration and a definition. Usually these pieces are split into separate files.

An object is a single instance of a class. You can create many objects from the same class type.

 

 

 

 

 

4. Explain basic data types in C++.

 

C++ supports a wide variety of data types and the programmer can select the data type appropriate to the needs of the application. Data types specify the size and types of value to be stored. However, storage representation and machine instructions to manipulate each data type differ from machine to machine, although C++ instructions are identical on all machines

Built in data types

char: For characters. Size 1 byte.

 

char ch = 'A';

int: For integers. Size 2 bytes.

 

int num = 100;

float: For single precision floating point. Size 4 bytes.

 

float num = 123.78987;

double: For double precision floating point. Size 8 bytes.

 

double num = 10098.98899;

bool: For booleans, true or false.

 

bool b = true;

wchar_t: Wide Character. This should be avoided because its size is implementation defined and not reliable.

 

User-defined data types

We have three types of user-defined data types in C++

1. struct

2. union

3. enum

 

Derived data types in C++

We have three types of derived-defined data types in C++

1. Array

2. Function

3. Pointer

 

 

 

 

5. Explain the term Reference Variable in detail.

 

Reference variable is an alternate name of already existing variable. It cannot be changed to refer another variable and should be initialized at the time of declaration and cannot be NULL. The operator ‘&’ is used to declare reference variable.

The following is the syntax of reference variable.

datatype variable_name; // variable declaration

datatype& refer_var = variable_name; // reference variable

Here,

datatype − The datatype of variable like int, char, float etc.

variable_name − This is the name of variable given by user.

refer_var − The name of reference variable.

The following is an example of reference variable.

 

Example

 

#include <iostream>

using namespace std;

int main() {

   int a = 8;

   int& b = a;

   cout << "The variable a : " << a;

   cout << "\nThe reference variable r : " << b;

   return 0;

}

 

 

6.What is Operator? What are its Types?

 

 

Operators are special type of functions, that takes one or more arguments and produces a new value. For example : addition (+), substraction (-), multiplication (*) etc, are all operators. Operators are used to perform various operations on variables and constants.

Types of operators

Assignment Operator

Mathematical Operators

Relational Operators

Logical Operators

Bitwise Operators

Shift Operators

Unary Operators

Ternary Operator

Comma Operator

Assignment Operator (=)

Operates '=' is used for assignment, it takes the right-hand side (called rvalue) and copy it into the left-hand side (called lvalue). Assignment operator is the only operator which can be overloaded but cannot be inherited.

 

Mathematical Operators

There are operators used to perform basic mathematical operations. Addition (+) , subtraction (-) , diversion (/) multiplication (*) and modulus (%) are the basic mathematical operators. Modulus operator cannot be used with floating-point numbers.

 

C++ and C also use a shorthand notation to perform an operation and assignment at same type. Example,

 

 

int x=10;

x += 4 // will add 4 to 10, and hence assign 14 to X.

x -= 5 // will subtract 5 from 10 and assign 5 to x.

Relational Operators

These operators establish a relationship between operands. The relational operators are : less than (<) , grater thatn (>) , less than or equal to (<=), greater than equal to (>=), equivalent (==) and not equivalent (!=).

 

You must notice that assignment operator is (=) and there is a relational operator, for equivalent (==). These two are different from each other, the assignment operator assigns the value to any Variables, whereas equivalent operator is used to compare values, like in if-else conditions, Example

 

int x = 10;  //assignment operator

x=5;         // again assignment operator

if(x == 5)   // here we have used equivalent relational operator, for comparison

{

    cout <<"Successfully compared";

}

Logical Operators

The logical operators are AND (&&) and OR (||). They are used to combine two different expressions together.

 

If two statement are connected using AND operator, the validity of both statements will be considered, but if they are connected using OR operator, then either one of them must be valid. These operators are mostly used in loops (especially while loop) and in Decision making.

 

Bitwise Operators

There are used to change individual bits into a number. They work with only integral data types like char, int and long and not with floating point values.

 

Bitwise AND operators &

Bitwise OR operator |

And bitwise XOR operator ^

And, bitwise NOT operator ~

They can be used as shorthand notation too, & = , |= , ^= , ~= etc.

 

Shift Operators

Shift Operators are used to shift Bits of any variable. It is of three types,

 

Left Shift Operator <<

Right Shift Operator >>

Unsigned Right Shift Operator >>>

Unary Operators

These are the operators which work on only one operand. There are many unary operators, but increment ++ and decrement -- operators are most used.

 

Other Unary Operators : address of &, dereference *, new and delete, bitwise not ~, logical not !, unary minus - and unary plus +.

 

Ternary Operator

The ternary if-else ? : is an operator which has three operands.

 

int a = 10;

a > 5 ? cout << "true" : cout << "false"

Comma Operator

This is used to separate variable names and to separate expressions. In case of expressions, the value of last expression is produced and used.

 

Example :

 

int a,b,c; // variables declaration using comma operator

a=b++, c++; // a = c++ will be done.

 

 

 

7.Explain Scope Resolution Operator with example.

 

The scope resolution operator ( :: ) is used for several reasons. For example: If the global variable name is same as local variable name, the scope resolution operator will be used to call the global variable. It is also used to define a function outside the class and used to access the static variables of class.

 

Here an example of scope resolution operator in C++ language,

 

Example

 

#include <iostream>

using namespace std;

char a = 'm';

static int b = 50;

 

int main() {

   char a = 's';

 

   cout << "The static variable : "<< ::b;

   cout << "\nThe local variable : " << a;

   cout << "\nThe global variable : " << ::a;

 

   return 0;

}

 

 

 

8. Write a program to print year is leap or not.

#include <iostream>

using namespace std;

 

int main() {

 

  int year;

  cout << "Enter a year: ";

  cin >> year;

 

  // leap year if perfectly divisible by 400

  if (year % 400 == 0) {

    cout << year << " is a leap year.";

  }

  // not a leap year if divisible by 100

  // but not divisible by 400

  else if (year % 100 == 0) {

    cout << year << " is not a leap year.";

  }

  // leap year if not divisible by 100

  // but divisible by 4

  else if (year % 4 == 0) {

    cout << year << " is a leap year.";

  }

  // all other years are not leap years

  else {

    cout << year << " is not a leap year.";

  }

 

  return 0;

}

 

 

 

 

9.What do you mean by dynamic initialization of a variable? Give an example.

Dynamic initialization of object refers to initializing the objects at run time i.e. the initial value of an object is to be provided during run time. Dynamic initialization can be achieved using constructors and passing parameters values to the constructors. This type of initialization is required to initialize the class variables during run time.

 

Dynamic initialization of objects is needed as

 

It utilizes memory efficiently.

 

Various initialization formats can be provided using overloaded constructors.

 

It has the flexibility of using different formats of data at run time considering the situation.

 

Example Code

#include <iostream>

using namespace std;

class simple_interest {

   float principle , time, rate ,interest;

   public:

      simple_interest (float a, float b, float c) {

         principle = a;

         time =b;

         rate = c;

      }

      void display ( ) {

         interest =(principle* rate* time)/100;

         cout<<"interest ="<<interest ;

      }

};

int main() {

   float p,r,t;

   cout<<"principle amount, time and rate"<<endl;

   cout<<"2000 7.5 2"<<endl;

   simple_interest s1(2000,7.5,2);//dynamic initialization

   s1.display();

   return 1;

}

 

 

10.What is access specifier? Enlist them.

 

The public keyword is an access specifier. Access specifiers define how the members (attributes and methods) of a class can be accessed. In the example above, the members are public - which means that they can be accessed and modified from outside the code.

 

However, what if we want members to be private and hidden from the outside world?

 

In C++, there are three access specifiers:

 

public - members are accessible from outside the class

private - members cannot be accessed (or viewed) from outside the class

protected - members cannot be accessed from outside the class, however, they can be accessed in inherited classes.

 

 

 

 

11.Explain different types of Inheritance with example.

 

Single Inheritance: In this type of Inheritance, only one class is derived from a single class (Base class). In an example below, Class B is derived from Class A. That means Class B will be having access to data members and member functions of Class A. Another example can be oe student can have only one id in college to access its information.

enter image description here

 

Multiple Inheritance: In this type of Inheritance, a class is derived from more than one super class. There can be more than one Super class and only one derived class. One derived class will implement properties of many Super classes. In this example, Class A extends properties of 3 Super Class, Class B, Class C and Class D. Another example can be many students belong to only one college.

 

enter image description here

 

Hierarchical Inheritance: In this type of Inheritance, one super class can have multiple deriving classes. There can be many classes deriving only one super Class. In this example, Class A is having 3 derived classes Class B, Class C and Class D. 3 derived classes will extend prosperities of single base class, Class A. Another example can be One Universities can have multiple colleges affiliated.

 

enter image description here

 

Multilevel Inheritance: In this type of Inheritance, Classes are inherited in the form of levels. For example, figure shows that Class C is derived from Class B and Class B is derived from Class A. Therefore , Inheritance can be carried out in multiple levels.

enter image description here

 

The derived class with multilevel inheritance can be declared as follows:

 

class A{……..};

 

class B extends A{….};

 

class C extends B{….};

 

The process can be extended to any number of levels.

 

Hybrid Inheritance: Sometimes, there is a need to implement more than one type of inheritances. In such situations, we combine two or more types of inheritances and design a Hybrid Inheritance. Given figure shows, Class B and Class D have single Inheritance designed, whereas Class A has two derived classes class B and Class C. In this Hybrid Inheritance has been carried out combining Single and Multiple Inheritance.

 

 

 

12.When do we make a class Virtual?

- An ambiguity can arise when several paths exist to a class from the same base class. This means that a child class could have duplicate sets of members inherited from a single base class.

- C++ solves this issue by introducing a virtual base class. When a class is made virtual, necessary care is taken so that the duplication is avoided regardless of the number of paths that exist to the child class.

- When two or more objects are derived from a common base class, we can prevent multiple copies of the base class being present in an object derived from those objects by declaring the base class as virtual when it is being inherited. Such a base class is known as virtual base class. This can be achieved by preceding the base class’ name with the word virtual.

 

 

13.What is Polymorphism? What is the difference between Compile Time and Runtime Polymorphism.

 

The word “polymorphism” means having many forms. In simple words, we can define polymorphism as the ability of a message to be displayed in more than one form. A real-life example of polymorphism is a person who at the same time can have different characteristics. Like a man at the same time is a father, a husband and an employee. So the same person exhibits different behavior in different situations. This is called polymorphism. Polymorphism is considered as one of the important features of Object-Oriented Programming. In C++, polymorphism is mainly divided into two types:

 

Compile-time Polymorphism

Runtime Polymorphism

Polymorphism-in-CPP

Types of Polymorphism

 

Compile-time polymorphism: This type of polymorphism is achieved by function overloading or operator overloading.

 

Function Overloading: When there are multiple functions with the same name but different parameters, then the functions are said to be overloaded. Functions can be overloaded by changing the number of arguments or/and changing the type of arguments.

 

Operator Overloading: C++ also provides the option to overload operators. For example, we can make use of the addition operator (+) for string class to concatenate two strings. We know that the task of this operator is to add two operands. So a single operator ‘+’, when placed between integer operands, adds them and when placed between string operands, concatenates them.

 

Runtime polymorphism: This type of polymorphism is achieved by Function Overriding.

Function overriding occurs when a derived class has a definition for one of the member functions of the base class. That base function is said to be overridden.

 

 

14.What is a Function Template? Write a function template for finding the largest number in a given array. The array parameter must be of generic data types.

 

A template is a simple yet very powerful tool in C++. The simple idea is to pass data type as a parameter so that we don’t need to write the same code for different data types. For example, a software company may need to sort() for different data types. Rather than writing and maintaining multiple codes, we can write one sort() and pass data type as a parameter.

C++ adds two new keywords to support templates: ‘template’ and ‘typename’. The second keyword can always be replaced by the keyword ‘class’.

 

Program Source Code:

 

#include<iostream>

using namespace std;

#define N 10

 

// defining the function template that

// returns the largest number of the array

// we consider type of array size directly integer

 

template <class T>

 

T find_max(T t[], int NO_OF_TERMS){

            T temp_max = t[0];

            for (int i = 0; i < NO_OF_TERMS; i++)

            {

                        if (temp_max < t[i] )

                        {

                                    temp_max = t[i];

                        }

            }

            return temp_max;

}

 

 

int main(){

            int numbers[N];

            cout<<"Enter numbers:"<<endl;

            for (int i = 0; i < N; i++)

            {

                        cin>>numbers[i];

            }

            cout<<"Largest Number of array is:"<<find_max(numbers,N)<<endl;

            // though you can make array size dynamic

            return 0;

}

 

 

 

 

15.Friend Class

 

Friend Class A friend class can access private and protected members of other class in which it is declared as friend. It is sometimes useful to allow a particular class to access private members of other class. For example, a LinkedList class may be allowed to access private members of Node.

 

A friend class can access both private and protected members of the class in which it has been declared as friend.

 

 

class Node {

private:

    int key;

    Node* next;

    /* Other members of Node Class */

 

    // Now class  LinkedList can

    // access private members of Node

    friend class LinkedList;

};

 

 

 

16.Inline Function

 

C++ inline function is powerful concept that is commonly used with classes. If a function is inline, the compiler places a copy of the code of that function at each point where the function is called at compile time.

 

Any change to an inline function could require all clients of the function to be recompiled because compiler would need to replace all the code once again otherwise it will continue with old functionality.

 

To inline a function, place the keyword inline before the function name and define the function before any calls are made to the function. The compiler can ignore the inline qualifier in case defined function is more than a line.

 

A function definition in a class definition is an inline function definition, even without the use of the inline specifier.

 

Following is an example, which makes use of inline function to return max of two numbers −

 

#include <iostream>

 

using namespace std;

 

inline int Max(int x, int y) {

   return (x > y)? x : y;

}

 

// Main function for the program

int main() {

   cout << "Max (20,10): " << Max(20,10) << endl;

   cout << "Max (0,200): " << Max(0,200) << endl;

   cout << "Max (100,1010): " << Max(100,1010) << endl;

  

   return 0;

}