// use of pointers

#include <iostream>
using std::cout;
using std::endl;

int main()
{
  double  a;
  double* aPtr = &a;

  *aPtr = 5.;
  cout << " a = " << a << "; aPtr = " << aPtr << "; *aPtr = " << *aPtr << endl;

  *aPtr *= 2.;
  cout << " a = " << a << "; aPtr = " << aPtr << "; *aPtr = " << *aPtr << endl;

  return 0;
}