//构造测试例

using namespace std;

int main ( void )
{
  int a = 0;

  const int * p1 = &a;  //推荐，指针常数
  int const * p2 = &a;  //不推荐，指针常数
  int * const p3 = &a;  //只能如此，常数指针

  int const b = 1;  //不推荐
  const int c = 2;  //推荐

  return ( 0 );
}