[c++] How to initialize const member variable in a class?

In C++ you cannot initialize any variables directly while the declaration. For this we've to use the concept of constructors.
See this example:-

#include <iostream>

using namespace std;

class A
{
    public:
  const int x;  
  
  A():x(0) //initializing the value of x to 0
  {
      //constructor
  }
};

int main()
{
    A a; //creating object
   cout << "Value of x:- " <<a.x<<endl; 
   
   return 0;
}

Hope it would help you!