Assignment operator - for not corrupting the state of object

If we have an object say a1 of type Array and if we have a line like a1 = a1 somewhere, the program results in unpredictable behavior because there is no self assignment check in the above code. To avoid the above issue, self assignment check must be there while overloading assignment operator. For example, following code does self assignment check.

// Overloaded assignment operator for class Array (with self

// assignment check)

Array& Array::operator = (const Array &rhs)

{

  /* SELF ASSIGNMENT CHECK */

  if(this != &rhs)

  {

    // Deallocate old memory

    delete [] ptr;

    // allocate new space

    ptr = new int [rhs.size];

    // copy values

    size = rhs.size;

    for(int i = 0; i < size; i++)

      ptr[i] = rhs.ptr[i];   

  } 

  return *this;

}

There is minor issue with above code. Even though we are doing self assignment 
check, there is a probability of corrupting the state of current/left
had side object.

We are doing 

delete[] ptr; //which is the member of Array class.

And then we are re-allocating the memory, what if there is a exception thrown
during allocation of memory?? BAD_ALLOW,NO_MEM?

To avoid such problems, first copy the ptr to local_ptr , allocate memory
 an then delete the old memory.

Array& Array::operator = (const Array &rhs)

{

  /* SELF ASSIGNMENT CHECK */

  if(this != &rhs)

  {
int *local_ptr = ptr;

    // allocate new space

    ptr = new int [rhs.size];

    // Deallocate old memory

    delete [] local_ptr;

    // copy values

    size = rhs.size;

    for(int i = 0; i < size; i++)

      ptr[i] = rhs.ptr[i];   

  } 

  return *this;

}