（精品课件）第二次作业（10.10评讲）.docVIP

P84 Exercise 3.1 E2 E3(b)(e) E2. Suppose that you are a financier and purchase 100 shares of stock in Company X in each of January, April, and September and sell 100 shares in each of June and November. The prices per share in these months were Jan Apr Jun Sep Nov $10 $30 $20 $50 $30 Determine the total amount of your capital gain or loss using (a) FIFO (first-in, first-out) accounting and (b) LIFO (last-in, first-out) accounting [that is, assuming that you keep your stock certificates in (a) a queue or (b) a stack]. The 100 shares you still own at the end of the year do not enter the calculation. Answer Purchases and sales: January: purchase 100* $10 = $1000 April: purchase 100 * $30= $3000 June: sell 100 *$20=$2000 September: purchase 100* $50 = $5000 November: sell 100* $30= $3000 With FIFO accounting, the 100 shares sold in June were those purchased in January, so the profit is $2000 - $1000 = $1000. Similarly, the November sales were the April purchase, both at $3000,so the transaction breaks even. Total profit = $1000. With LIFO accounting, June sales were April purchases giving a loss of $1000 ($2000-$3000), and November sales were September purchases giving a loss of $2000 ($3000 - $5000). Total loss = $3000. E3. Use the methods for stacks and queues developed in the text to write functions that will do each of the following tasks. In writing each function, be sure to check for empty and full structures as appropriate. Your functions may declare other, local structures as needed. (b) Move all the entries from a Queue onto a Stack. Error_code queue_to_stack(Stack s, Queue q) /* Pre: The Stack s and the Queue q have the same entry type. Post: All entries from q have been moved to s. If there is not enough room in s to hold all entries in q return a code of overflow, otherwise return success. */ { Error_code outcome = success; Entry item; while (!q.empty( )) { q.retrieve(item); outcome=s.push(item); if (outcome == overflow) return outcome; q.serve( ); } ret