ACCESSING DATA MEMBERS OF CLASS

ACCESSING DATA MEMBERS OF CLASS

The data members and member functions of class can be accessed using the dot(‘.’) operator with the object.

For example  if the name of object is obj and you want to access the member function with the name printName() then you will have to write obj.printName() .

If, the data member is defined as private or protected, then we cannot access the data variables directly. Then we will have to create special public member functions to access, use or initialize the private and protected data members. These member functions are also called Accessors and Mutator methods or getter and setter functions.

Accessing Public Data Members

Following is an example to show you 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()

{ Student A;

 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;

}

Accessing Private Data Members

To access, use and initialize the private data member you need to create getter and setter functions, to get and set the value of the data member.

The setter function will set the value passed as argument to the private data member, and the getter function will return the value of the private data member to be used. Both getter and setter function must be defined public.

Example :

class Student

{   private:    // private data member

 int rollno;

public:     // public accessor and mutator functions

 int getRollno()

 {

  return rollno;

 }

void setRollno(int i)

 {

  rollno=i;

 }

};

int main()

{ Student A;

 A.rollono=1;  //Compile time error

 cout<< A.rollno; //Compile time error

A.setRollno(1);  //Rollno initialized to 1

 cout<< A.getRollno(); //Output will be 1

}

So this is how we access and use the private data members of any class using the getter and setter methods. We will discuss this in more details later.

Accessing Protected Data Members

Protected data members, can be accessed directly using dot (.) operator inside the subclass of the current class, for non-subclass we will have to follow the steps same as to access private data member.

Example to show  all  the  data  members  in a class

// C++ program to demonstrate

// accessing of data members

#include <bits/stdc++.h>

using namespace std;

class Geeks

{

    // Access specifier

    public:

    // Data Members

    string geekname;

    // Member Functions()

    void printname()

    {

       cout << "Geekname is: " << geekname;

    }

};

int main() {

  // Declare an object of class geeks

    Geeks obj1;

    // accessing data member

    obj1.geekname = "Abhi";

 // accessing member function

    obj1.printname();

    return 0;

}

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