******** fig6.4a **********

	PRIORITY_QUEUE
	create_pq( unsigned int max_elements )
	{
		PRIORITY_QUEUE H;

/*1*/		if( max_elements < MIN_PQ_SIZE )
/*2*/			error("Priority queue size is too small");

/*3*/		H = (PRIORITY_QUEUE) malloc( sizeof( struct heap_struct ) );
/*4*/		if( H == NULL )
/*5*/			fatal_error("Out of space!!!");

			/* Allocate the array + one extra for sentinel */
/*6*/		H->elements=(element_type *)malloc((max_elements+1)*sizeof(element_type));
/*7*/		if( H->elements == NULL )
/*8*/			fatal_error("Out of space!!!");

/*9*/		H->max_heap_size = max_elements;
/*10*/		H->size = 0;
/*11*/		H->elements[0] = MIN_DATA;

/*12*/		return H;
	}