#include <memory>
#include <iostream>
#include <string>
#include "point.h"

using namespace std;

void f(Point *pp1){
  auto_ptr<Point>ap1(pp1),
                 ap2(new Point(3,4));

  // Use auto_ptr<Point> like Point*
  cout << "ap1: " << *ap1 << endl;   // (1,2)
  cout << "ap2: " << *ap2 << endl;   // (3,4)

  ap2->move(1,1);
  cout << "ap1-ap2 dist: " << ap1->distance_to(*ap2) << endl;  // 4.24264

  // Destructive copying:  ap2 is deleted
  //                       ap2 becomes a pointer to ap1
  //                       ap1 is unbound (corresponding to NULL).
  ap2 = ap1;

  if (ap1.get())                        // ap1 is NULL      !!!
     cout << "ap1: " << *ap1 << endl;  
  else
     cout << "ap1 is NULL" << endl;

  if (ap2.get())                        // (1,2)
     cout << "ap2: " << *ap2 << endl;
  else
     cout << "ap2 is NULL" << endl;

  // ap1 and ap2 are deleted on exit from f
  // ap2 refers to pp1, which therefore is deleted.
}

int main(){
  Point *p = new Point(1,2);
  f(p);

  cout << "p: " << *p << endl; // Unsafe! 
                               // p has been deleted by f.
}