#include <iostream>
using namespace std ;

int main() {

const double PI = 3.14159268 ;

double * const ptr3 = &PI ;        // not OK
const double * const ptr4 = &PI ;  // OK


double x = 1.414 ;
double * const ptr3a = &x ;   //OK

*ptr3a = 2.0 ;    // allowed
ptr3a++ ;         // not allowed

}