600:/lib/trade.c (/lib/trade.c)
(int *) calc_coins(int price, int *arr, string str)
/*
 * Function name: calc_coins
 * Description:   Reduce from bottom of array cosidering the price
 * Arguments:     price - the price to pay
 *                arr - the array holding the coins
 *                str - a string describing how object wants to get change
 * Returns:       The array object should pay, reduced
 */
