void  IntArray::
init ( const int *data, int sz)
{ 
                                                
        assert( (0 <= sz) && (sz <= MAXINT));

        d_num_elements = sz;
        if ( 0 == d_num_elements ){          // if no elements in array
                d_array = NULL;                  // array points to NULL
        }
        else{
                d_array = new int [d_num_elements];
                                                     // allocate memory
                                                     // if new returns NULL then no
                                                     // more available memory
                assert ( NULL != d_array );
        }
        for (int i=0; i < sz; i++ ){
                                           
                if ( NULL == data ){
                        self [i] = 0;
                }
                else{
                        self[i] = data[i];
                }
        }
}