This document discusses data members and member functions in object-oriented programming. It defines data members as variables declared inside a class and member functions as functions declared inside a class. It covers accessing public, private, and protected data members, defining member functions inside and outside the class, and different types of member functions like static, const, inline, and friend functions. The document provides examples and explanations for each concept to help explain how data members and member functions work in object-oriented programming.

1. DATA MEMBERS AND MEMBER
FUNCTIONS IN OBJECT
ORIENTED PROGRAMMING
Presented by :-
DC2016BTE0044 PUSPITA DAS
DC2016BTE0185 SHREYALAXMITALUKDAR
DC2016BTE0195 MARLOM BEY

2.  Introduction
 Static Data Members
 Accessing Data Members
 Defining Member Functions
 Types of Member Functions
 Conclusion
 References
Contents

3. Introduction
 Data Members:
O The variables declared inside the class are known as data members.
O Data members may be private or public.
 Member functions:
O The functions declared inside the class are known as member functions.
O Member functions are methods or functions that are defined inside of
objects.
O Generally used to manipulate data members and other object data.

4. Static Data Members
 Static Data Members are those which are declared by using the static
keyword in front of the data members.
 Static Data Members are always used in the static member function.
 The static data members are always assigned some values from the
outside of the class.
Syntax:
classWidget {
...
static unsigned int g_serial ;
...
} ;

5. Accessing Data Members
 Accessing Public Data Members
 Accessing Private Data Members
 Accessing Protected Data Members

6. Accessing Public Data Members
 Following is an example to show how to initialize and use the public data members
using the dot (.) operator and the respective object of class.
class Student
{
public:
int rollno;
string name;
};
int main()
{
StudentA;
Student B;
A.rollno=1;
A.name="Adam";
B.rollno=2;
B.name="Bella";
cout <<"Name and Roll no of A is :"<<A.name << A.rollno;
cout <<"Name and Roll no of B is :"<< B.name << B.rollno;
}

7. Accessing Private Data Members
 To access, use and initialize the private data member we need to create getter and setter
functions, to get and set the value of the data member.
class Student
{
private:
int rollno;
public: // public getter and setter functions
int getRollno()
{
return rollno;
}
void setRollno(int i)
{
rollno=i;
}
};
int main()
{
Student A;
A.rollono=1;
cout<< A.rollno;
A.setRollno(1);
cout<< A.getRollno(); //Output will be 1
}

8. Accessing Protected Data Members
 Protected data members, can be accessed directly using dot (.)
operator inside the subclass of the current class
 Protected data members can be accessed in the same way as
public data members f.rom friend functions or classes and from
derived classes.

9. Defining Member Function
 Inside the class definition
 Outside the class definition

10. InsideThe Class Definition
 A member function of a class can be defined inside the class. However,
when a member function is defined inside the class, the class name and
the scope resolution operator are not specified in the function header.
Example :
class book
{
char title[30];
float price;
public:
void getdata(char [],float); II declaration
void putdata()//definition inside the class
{
cout<<"nTitle of Book: "<<title;
cout<<"nPrice of Book: "<<price;
};

11. OutsideThe Class Definition
 Defining a member function outside a class requires the function declaration to be
provided inside the class definition.
Example:
Class book
{
// body of the class
} :
void book :: getdata(char a[],float b)
{
// defining member function outside the class
Strcpy(title,a):
price = b:
}
void book :: putdata ()
{
cout<<"nTitle of Book: "<<title;
cout<<"nPrice of Book: "<<price;
}

12. TYPES OF MEMBER FUNCTION
 Simple Function
 Static Function
 Const Function
 Inline Function
 Friend Function

13. Simple Function
 These are the basic member function, which don,t have any
special keyword like static etc. as prefix.
Example:
return_type functionName(parameter_list)
{
function body;
}

14. Static Member Function
 A function is made static by using static keyword with function name.
 It can be called using the object and the direct member access (.) operator.
But, its more typical to call a static member function by itself, using class
name and scope resolution (::) operator.
A function is made static by using static keyword with function name
Example:
class X
{
public:
static void f(){};
};
int main()
{
X::f(); // calling member function directly with class name
}

15. Const Member Functions
 Const keyword makes variables constant, that means once
defined, there values can't be changed.
 When used with member function, such member functions can
never modify the object or its related data members.
//Basic Syntax of const Member Function
void fun() const {}

16. Inline Member Functions
 All the member functions defined inside the class definition are by default
declared as Inline.
 Member functions containing a few lines of code are usually declared inline.
For example:
ClassY
{
char*a ;
public:
Char* f();{return a;}
};
Is equivalent to
Char Z
{
char*a;
Public:
char* f();
};
Inline char* Z::f()
{return a;}

17. Friend Member Functions
 Friend functions are made to give private access to non-class functions.You can
declare a global function as friend, or a member function of other class as friend.
Example:
class WithFriend
{
int i;
public:
friend void fun(); // Global function as friend
};
void fun()
{
withFriend wf;
wf.i=10; //Access to private data member
cout << wf.i;
}
int main()
{
fun(); //Can be called directly
}

18. Conclusion
 A static member function can only access static data members of the
class, it cannot access instance data members.
 A private member function can only be called by another function
that is a member class.
 Protected keywords are only used in the inheritance context.
 Objects created by object oriented programs can easily be reused in
other programs

19. References
■ Books
[1]. By E Balagurusamy “Object Oriented ProgrammingWith C++” ,TATA McGraw-
Hill Publishing Company Limited, 2008
■ Web Links
[2]. https://www3.ntu.edu.sg/home/ehchua/programming/cpp/cp3_OOP.html
---OOP Basics
[3]. http://www.studytonight.com/cpp/accessing-data-
members.php
---Accessing Data Members
[4]. http://www.studytonight.com/cpp/member-functions-cpp.php
---Member Functions
[5]. http://www.studytonight.com/cpp/types-of-member-function.php
---Types of Member Function

20. THANK YOU