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COMPUTER SCIENCE 255

SECOND HOUR EXAM





NAME ___________________________

















							 6 pages, 100 pts.
							2:00 PM Thursday, Nov. 2

1.	Basic questions 

a.	(10 pts.)	What are the five steps in the life cycle model 
for software?  Describe each briefly.


b.	(10 pts.)	What is a prototype?  Why is it useful?











c.	(5 pts.)	What is a blocking factor?  How (and 
where) is it specified in a COBOL program?











d.	(10 pts.)	What is multiple buffering?  Why is it 
useful?  How (and where) is it specified in a COBOL 
program?

2.	Design (20 pts.)

	An application is to be designed to store information about 
employees and the projects that employees work on.  We want 
to store and employee's employee number, name, supervisor 
number, and salary.  For projects, we want to store the project 
name and a contract number and the employee number of the 
lead engineer for the project.  We also want to know who 
works on what projects, subject to the constraint (or lack 
thereof) that each employee can work on several projects (and 
devotes a percentage of her or his time to that project) and 
each project can have several employees working on it.

	Write an entity-relationship diagram for this situation, and 
briefly describe the files that you might generate from the 
diagram.  Identify primary and foreign keys.

3.	Tables (20 pts.)	

	Write a table description for a table of records describing parts.  
Each part description consists of a five character part number, 
a 20 character part description, and a three digit quantity field.  
The table should be written so that a binary search verb can be 
used (the table will be in order by part number).  After the 
table description is written, write the COBOL binary search 
verb necessary to find part "12345".  Display the part 
description if found, an error message if the part is not found.

4.	A level break problem (25 pts.)	

	Records in the file CARSALES.DAT consist of a sales manager 
name, a salesperson name (both 20 characters) and a car sale 
(PIC 9(5)v99).  Each sales manager manages a number of 
salespersons and each salesperson reports to only one sales 
manager.  The records are in order by salesmanager name 
followed by salesperson name.  Write the PROCEDURE DIVISION 
entries necessary to produce a report of the data in CARSALES, 
with subtotals for each sales manager, each salesperson, and 
the entire dealership.