Name USC loginid e g ttrojan CS 455 Midterm Exam 1 Spring 2011 Bono Feb 17 2011 There are 4 problems on the exam with 50 points total available There are 7 pages to the exam including this one make sure you have all of them There is also a double sided one page code handout that accompanies the exam If you need additional space to write any answers you may use the backs of exam pages just direct us to look there If you have scratch work in addition to your answer circle your final answer so we know what to grade Put your name and USC ID number at the top of the exam Please read over the whole test before beginning Good luck Remote DEN students only Do not write on the backs of pages If additional space is needed ask proctor for additional blank page s put your name on them and attach them to the exam value Problem 1 10 pts Problem 2 10 pts Problem 3 10 pts Problem 4 20 pts TOTAL 50 pts score Problem 1 10 pts Consider the following code fragment Note more about Point class on code handout Point p1 new Point 10 20 Point p2 new Point p1 Point p3 p1 p1 translate 5 10 p2 translate 5 10 p3 translate 5 10 System out println p1 p2 p3 Part A 5 In the space below draw a box and pointer diagram a k a memory diagram showing all object variables objects and their state as they have changed during the code sequence Part B 3 What is printed by the code For the purpose of this problem assume a Point is printed as follows x y Part C 2 How many Point objects are created by the code above 2 Problem 2 10 pts Change the CashRegister class from the textbook so a manager can track some information about the day s sales the class itself and space for your answer is given on the next two pages Here is a sample interaction to show the new functionality calls to new methods shown in bold CashRegister reg new CashRegister reg recordPurchase 3 95 reg recordPurchase 22 99 System out println reg getTotal reg enterPayment 30 System out println reg giveChange first customer finishes transaction reg recordPurchase 7 24 reg recordPurchase 7 24 reg recordPurchase 42 50 System out println reg getTotal reg enterPayment 60 System out println reg giveChange second customer finishes transaction many other sales take place throughout the day reg recordPurchase 4 99 System out println reg getTotal reg enterPayment 10 System out println reg giveChange last customer of the day finishes transaction call new methods for end of the day processing System out println reg getTotalSales System out println reg avgSalesPerCustomer reg reset reset all totals for the next day 3 Problem 2 cont Here and continued on the next page is the complete CashRegister class definition without the new functionality Add your new code inline with the existing code or to the right of the code with arrows clearly indicating where your new code would be inserted For your convenience we already added the empty method bodies in bold A cash register totals up sales and computes change due public class CashRegister private double purchase private double payment Constructs a cash register with no money in it public CashRegister purchase 0 payment 0 Records the sale of an item param amount the price of the item public void recordPurchase double amount double total purchase amount purchase total Gets total of all purchases made by this customer public double getTotal return purchase Enters the payment received from the customer param amount the amount of the payment public void enterPayment double amount payment amount CashRegister class definition continued next page 4 Problem 2 cont Computes the change due and resets the machine for the next customer return the change due to the customer public double giveChange double change payment purchase purchase 0 payment 0 return change Returns total sales since the last reset if before first reset sales since it was created return total sales public double getTotalSales Computes the average sales per customer how much each customer spent on average since last reset if before first reset avg since it was created return average sales per customer public double avgSalesPerCustomer Resets the machine to initial state Zeroes out all sales etc public void reset end of class CashRegister 5 Problem 3 10 pts total Implement the formatSentence method below that reads words from the given scanner until end of file printing them out formatted as a sentence A sentence has one space between each word and a period right after the last word Example input The big went dog home Corresponding output The big dog went home prints a version of text read from parameter in formatted as a sentence if there are no words to read from in prints nothing public void formatSentence Scanner in 6 Problem 4 20 pts total Implement the hasPeak method which tells us whether its array of int data values when plotted has a single peak This means that the sequence of values consists wholly of an increasing part followed by a decreasing part You may assume no two consecutive values in the array are the same i e no flat areas Here are several examples vals hasPeak vals vals hasPeak vals 3 7 false 3 5 2 true 7 3 false 3 2 1 false 3 5 9 2 true 3 5 2 3 false 3 5 9 3 2 true 2 false empty false public boolean hasPeak int vals 7