How to use Const with C++ Classes

Introduction:

Dear students today we will talk about the constant (const) keyword in C++ class structure. In C++ we can use const in a class in three ways;

• const as a data member
• const as a member function
• const ad an object of a class

Important points to remember;

Constant data members can only be assigned by the constant member functions or by the member initialization list of a constructor. In this example, I am using member initialization list to assign the values to the constant data member of class student.

The code snippet is given below;

Code:

////////////////////////////////////////////C++ Code//////////////////////////////////////////////////////////////////

#include <iostream.h>

using namespace std;

class Student

{

  const int Rollno;// constant data member

  string name;

  float cgpa;

  public:

  Student(int r): Rollno(r),name(""),cgpa(0) //Member initialization list

  {

      

      

  }

  

  int getRollno(){return Rollno;}

    

    

};

int main()

{Student obj1(20);

   cout << " calling constnt object " << obj1.getRollno()<<endl; 

   

   system("pause");

   return 0;

}

////////////////////////////////////////////////end////////////////////////////////////////////////////////

Out put

By Hafiz Muhammad Umar Hayat

Email: hafizmohemmedumar@gmail.com