Using the const keyword to optimize your code

We have already seen in previous recipes that a const keyword is used to make data or a pointer constant so that we cannot change the value or address, respectively. There is one more advantage of using the const keyword. This is particularly useful in the object-oriented paradigm.

Getting ready

For this recipe, you will need a Windows machine and an installed version of Visual Studio.

How to do it…

In this recipe, we will find out how easy it is to use the const keyword effectively:

#include <iostream>

class A
{
public:

  void Calc()const
  {
    Add(a, b);
    //a = 9;       // Not Allowed
  }
  A()
  {
    a = 10;
    b = 10;

  }
private:
  
  int a, b;
  void Add(int a, int b)const
  {
    
    std::cout << a + b << std::endl;
  }
};

int main()
{
  
  A _a;
  _a.Calc();

  int a;
  std::cin >> a;

  return 0;
}

How it works…

In this example, we are writing a simple application to add two numbers. The first...