545:/lib/trade.c (/lib/trade.c)
(int *) calc_change(int price, int *arr, string str)
/*
 * Function name: calc_change
 * Description:   Check what change to give the object considered the price
 *                and what is about to be payed. If no array then it's a sale
 *                and the changed is based on the price alone.
 * Arguments:     price - the price in cc
 *                arr - the array describing what we already pays
 *                str - the string describing what types the object wants
 * Returns:       The array holding the coins the object should be given
 */
