Assignment
Aim:
Developing programs via functional decomposition and pointers.
On completion you should know how to:
- design a program by decomposing the problem into small functional units,
- implement a program using pointers and dynamic memory,
- produce a database program for maintaining records.
Requirements:
You are provided with an incomplete database program for accessing an electronic phone book. Your task is to firstly convert memory management from static to dynamic memory and implement the main search function. Each record in the database contains the following information:
Phone Number // 8 digit number
Family Name; // up to 20 chars
Given Name; // up to 20 chars
Street Number; // number 1..2500
Street Name // up to 30 chars
Suburb // up to 30 chars
PostCode // 4 digit number
The program is implemented in 3 files: main.cpp contains the text-menu based user interface. ass2.h contains public function prototypes. ass2.cpp contains the function definitions of the database program. Test data is provided in phone.txt.
Step 1: involves converting the program from static to dynamic memory. To do this, first convert the DB array into an array of pointers to PhoneRecords:
PhoneRecord *gPhoneRecs[cMaxRecs];
Then modify the ReadFile() function so that as records are read, dynamic memory is allocated to array elements using the new operator:
gPhoneRecs[i] = new PhoneRecord;
This statement should go just after the break statement within in the read file loop. Now convert all references to the PhoneRecord fields to ‘->'. e.g.
fin >> gPhoneRecs[i]->PostCode;
Also, complete the DisplayRecord() function for displaying records in the DB array five records at a time. (Make sure the format complies with that shown below.) Example:
Command: d
56391746 John Johns, 520 Park Lane, Oak Flats, 2532
14053398 Jill Jackson, 153 Seaview Dr, Mt Keira, 2211
70399355 Jack Hendly, 134 Parker St, Blacktown, 5933
83438529 Chris Smith, 788 Crest St, Albion Park, 2544
41878844 Joe Jones, 89 Keira Lane, Kanahooka, 2322 Display more records? y/n:
92392252 Jack Bell, 707 Cherry Lane, Waterfall, 2233
93037935 Lauren Hendly, 557 Cope St, Kanahooka, 2322
50981291 Mary Hendly, 94 Crest St, Blacktown, 5344
93220958 Jenifer Parker, 415 Park Lane, Oak Flats, 2456
23339704 Mavis Johnstone, 904 Peace Dr, Mt Keira, 2211 Display more records? y/n:
Step 2: involves implementing an AddRecord() function for adding a new record to the DB:
a adds a new record to the file
Example:
Command > a
Adding a new Record to Database...
Enter phone number: 42219999
Enter family name: Gates
Enter given name: Bill
Enter street number: 123
Enter street name: Silicon Dr
Enter suburb name: Silicon Valley
Enter postcode: 9999
A new record has been added to the database
...there are 245 records in the database
Note: The new record should be both added to the gPhoneRecs[] array and the data file. To append the record data to the end of the data file use:
fout.open(filename, ios::app); // opens file in append mode.
Step 3: involves implementing a Search() function for searching the database. The search function should request the Phone number from the user and display the matching phone number on the screen. Example:
Command > s
Enter phone number: 85332209
Jill, Dell, 779, Parker St, Smithville, 2958
Command > s
Enter phone number: 88884444
Record not found!
Also, implement a CleanUp() function for deleting all memory in the DB array when the program ends to avoid a memory leak.
Step 4: Add an erase record menu item to main.cpp e.g.:
"(e) Erase record"
and implement this function in ass2.cpp. e.g.
Command > e
Enter phone number: 88884444
88884444 has been erased from the database
...there are 244 records in the database
Attachment:- Assignment-CPP.zip