《C++大学教程第五版》课后习题答案第39章.docx

1、C+大学教程第五版课后习题答案第39章3.11GradeBook类定义：#include / program uses C+ standard string classusing std:string;class GradeBookpublic: / constructor initializes course name and instructor name GradeBook( string, string ); void setCourseName( string ); / function to set the course name string getCourseName(); /

2、 function to retrieve the course name void setInstructorName( string ); / function to set instructor name string getInstructorName(); / function to retrieve instructor name void displayMessage(); / display welcome message and instructor nameprivate: string courseName; / course name for this GradeBoo

3、k string instructorName; / instructor name for this GradeBook; / end class GradeBook类成员函数：#include using std:cout;using std:endl;#include GradeBook.h/ constructor initializes courseName and instructorName / with strings supplied as argumentsGradeBook:GradeBook( string course, string instructor ) set

4、CourseName( course ); / initializes courseName setInstructorName( instructor ); / initialiZes instructorName / end GradeBook constructor/ function to set the course namevoid GradeBook:setCourseName( string name ) courseName = name; / store the course name / end function setCourseName/ function to re

5、trieve the course namestring GradeBook:getCourseName() return courseName; / end function getCourseName/ function to set the instructor namevoid GradeBook:setInstructorName( string name ) instructorName = name; / store the instructor name / end function setInstructorName/ function to retrieve the ins

6、tructor namestring GradeBook:getInstructorName() return instructorName; / end function getInstructorName/ display a welcome message and the instructors namevoid GradeBook:displayMessage() / display a welcome message containing the course name cout Welcome to the grade book forn getCourseName() ! end

7、l; / display the instructors name cout This course is presented by: getInstructorName() endl; / end function displayMessage测试文件：#include using std:cout; using std:endl;/ include definition of class GradeBook from GradeBook.h#include GradeBook.h/ function main begins program executionint main() / cre

8、ate a GradeBook object; pass a course name and instructor name GradeBook gradeBook( CS101 Introduction to C+ Programming, Professor Smith ); / display initial value of instructorName of GradeBook object cout gradeBook instructor name is: gradeBook.getInstructorName() nn; / modify the instructorName

9、using set function gradeBook.setInstructorName( Assistant Professor Bates ); / display new value of instructorName cout new gradeBook instructor name is: gradeBook.getInstructorName() nn; / display welcome message and instructors name gradeBook.displayMessage(); return 0; / indicate successful termi

10、nation / end main3.12类定义：class Accountpublic: Account( int ); / constructor initializes balance void credit( int ); / add an amount to the account balance void debit( int ); / subtract an amount from the account balance int getBalance(); / return the account balanceprivate: int balance; / data membe

11、r that stores the balance; / end class Account类成员函数：#include using std:cout;using std:endl;#include Account.h / include definition of class Account/ Account constructor initializes data member balanceAccount:Account( int initialBalance ) balance = 0; / assume that the balance begins at 0 / if initia

12、lBalance is greater than 0, set this value as the / balance of the Account; otherwise, balance remains 0 if ( initialBalance 0 ) balance = initialBalance; / if initialBalance is negative, print error message if ( initialBalance 0 ) cout Error: Initial balance cannot be negative.n balance ) / debit a

13、mount exceeds balance cout Debit amount exceeded account balance.n endl; if ( amount = balance ) / debit amount does not exceed balance balance = balance - amount; / end function debit/ return the account balanceint Account:getBalance() return balance; / gives the value of balance to the calling fun

14、ction / end function getBalance测试函数：#include using std:cout;using std:cin;using std:endl;/ include definition of class Account from Account.h#include Account.h/ function main begins program executionint main() Account account1( 50 ); / create Account object Account account2( 25 ); / create Account o

15、bject / display initial balance of each object cout account1 balance: $ account1.getBalance() endl; cout account2 balance: $ account2.getBalance() endl; int withdrawalAmount; / stores withdrawal amount read from user cout withdrawalAmount; / obtain user input cout nattempting to subtract withdrawalA

16、mount from account1 balancenn; account1.debit( withdrawalAmount ); / try to subtract from account1 / display balances cout account1 balance: $ account1.getBalance() endl; cout account2 balance: $ account2.getBalance() endl; cout withdrawalAmount; / obtain user input cout nattempting to subtract with

17、drawalAmount from account2 balancenn; account2.debit( withdrawalAmount ); / try to subtract from account2 / display balances cout account1 balance: $ account1.getBalance() endl; cout account2 balance: $ account2.getBalance() endl; return 0; / indicate successful termination / end main3.13类定义：#includ

18、e / program uses C+ standard string classusing std:string;/ Invoice class definitionclass Invoicepublic: / constructor initializes the four data members Invoice( string, string, int, int ); / set and get functions for the four data members void setPartNumber( string ); / part number string getPartNu

19、mber(); void setPartDescription( string ); / part description string getPartDescription(); void setQuantity( int ); / quantity int getQuantity(); void setPricePerItem( int ); / price per item int getPricePerItem(); / calculates invoice amount by multiplying quantity x price per item int getInvoiceAm

20、ount(); private: string partNumber; / the number of the part being sold string partDescription; / description of the part being sold int quantity; / how many of the items are being sold int pricePerItem; / price per item; / end class Invoice类成员函数：#include using std:cout;using std:endl;/ include defi

21、nition of class Invoice from Invoice.h#include Invoice.h/ Invoice constructor initializes the classs four data membersInvoice:Invoice( string number, string description, int count, int price ) setPartNumber( number ); / store partNumber setPartDescription( description ); / store partDescription setQ

22、uantity( count ); / validate and store quantity setPricePerItem( price ); / validate and store pricePerItem / end Invoice constructor/ set part numbervoid Invoice:setPartNumber( string number ) partNumber = number; / no validation needed / end function setPartNumber/ get part numberstring Invoice:ge

23、tPartNumber() return partNumber; / end function getPartNumber/ set part descriptionvoid Invoice:setPartDescription( string description ) partDescription = description; / no validation needed / end function setPartDescription/ get part descriptionstring Invoice:getPartDescription() return partDescrip

24、tion; / end function getPartDescription/ set quantity; if not positive, set to 0void Invoice:setQuantity( int count ) if ( count 0 ) / if quantity is positive quantity = count; / set quantity to count if ( count = 0 ) / if quantity is not positive quantity = 0; / set quantity to 0 cout 0 ) / if pric

25、e is positive pricePerItem = price; / set pricePerItem to price if ( price = 0 ) / if price is not positive pricePerItem = 0; / set pricePerItem to 0 cout npricePerItem cannot be negative. pricePerItem set to 0.n; / end if / end function setPricePerItem/ get price per itemint Invoice:getPricePerItem

26、() return pricePerItem; / end function getPricePerItem/ calulates invoice amount by multiplying quantity x price per itemint Invoice:getInvoiceAmount() return getQuantity() * getPricePerItem(); / end function getInvoiceAmount测试函数：#include using std:cout;using std:cin;using std:endl;/ include definit

27、ion of class Invoice from Invoice.h#include Invoice.h/ function main begins program executionint main() / create an Invoice object Invoice invoice( 12345, Hammer, 100, 5 ); / display the invoice data members and calculate the amount cout Part number: invoice.getPartNumber() endl; cout Part description: invoice.getPartDescription() endl; cout Quantity: invoice.getQu