C++ auto_ptr template query

["Digvijoy Chatterjee" <chatterjee dot digvijoy at gmail dot com>]

Hello,
Can anyone help me find a way  prevent memory leaks in the type of code below
i tried auto_ptr template but I am still loosing 40 bytes. ([10] ints
* 4 in the Class Car)
---------------------------------------------------------
class Motor
{
public:
 static int i;
   Motor ()
 {
     if (i++ == 2)
     throw 46;
 }
  ~Motor (){}
};

class Car
{
public:
   Car ()
 {
   a = new int[10];
   M1 = new Motor;
 }
 ~Car ()
 {
   delete []a;
   delete M1;
 }
private:
 int *a;
 Motor * M1;
};

int  Motor::i = 0;
int main ( )
{
 try
 {
   auto_ptr < Car > auto_car (new Car[3]);
 } catch (int)
 {
   cout << "Car caught an int thrown from motor" << endl;
 }
}
-------------------
The Car[3] object is not fully constructed ,so its destructor is not
called ,but auto_car is and so when the try scope ends ,auto_car
should ensure that the object it wraps gets deleted which should call
delete [] a and remove int*a[10], thats my flawed logic i suppose
,correct me if this is wrong
Regards
Digz