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.Bothexperienced and naive users must be given instructions for running the program.Furthermore, someone wishing to modify the program must be given informationabout what design decisions were made, and what implementation and testingproblems were encountered.Even the original programmer needsdocumentation, to be able to modify the program long after it has beendeveloped.It is always extremely surprising to realize how quickly one forgetsdesign decisions along with the reasons why they were made.Documentation does not begin in this sixth step of our problem solving method.It begins with the first step of program development and continues throughoutthe lifetime of the program.The program itself, with its comments, is calledinternal documentation, whereas the testing information is part of the externaldocumentation(all documentation other than the program listing).At eachstep of the program development process, some documentation is produced, asshown in Figure 10.9. 470 Chapter 10 The Seven-Step MethodFigure 10.9 Documentation during the Seven StepsSteps Documentation produced1.Problem definition The problem specifications, including aprecise description of the input/output2.Solution design A description of the design, with structurecharts and modular design charts3.Solution refinement Data specifications, pseudocode, and unitinterfaces4.Testing strategy An outline of the testing strategy, test data,development and expected results, as well as pseudocodefor drivers and stubs5.Program coding and testing The program code (internal documentation),test data, and results7.Program maintenance Change log and, if the changes areimportant, all the documentation normallyproduced for a complete program (as in thepreceding steps)All of this documentation must be collected, and must be kept current (withperhaps the exception of the pseudocode) throughout the lifetime of thesoftware.In addition to the above documentation produced at each step, someadditional user documentation may be needed.This documentation mustprovide the user with enough information to be able to use the program and itsfunctions fully, without providing the mental burden of implementationdetails.This type of documentation is often referred to as a user s manual .It is usually helpful to develop a preliminary version of the user documentationduring the problem definition step and then to refine it once coding and testingare done.This preliminary version of the user documentation can be given tothe users, to verify that you have correctly understood the problem and areproducing a program that will satisfy the users.Documentation Completion ApplicationThe documentation will include the problem definition, the design documents, adescription of the testing performed, a history of the program development andits different versions, and a user s manual.Such a manual is designed for anaive user and illustrates how to prepare input data, how to run the program,and how to obtain and interpret results.The following is a sample ACMEPayroll User s Manual:ACME Payroll User's ManualPayroll is a program to compute and display the weekly payof hourly paid employees.For each employee, it will read aseries of four data items separated by at least one blank:number of hours worked during the week (0 55), hourly rateof pay ($3.50 $16.50), number of dependents (0 12), and nameof employee (20 characters).If the data are valid, theprogram will compute and display federal (18% of taxableincome), state (3% of taxable income), and social security Section 10.2 The Seven-Step Method and Applications 471(5% of gross pay) withholdings, as well as gross and net payfor the employee." The program will read data for each employee from thefile Payroll.data until it reaches the end of thefile.It will produce results on the screen.Inputdata format is such that three integer values precedea character string, as in4500 600 3 Allan Mackenziefor 45.00 hours worked, $6.00 per hour, and 3dependents." Output data will be written one line at a time, eachline corresponding to an employee.A normal outputline will consist of a 20-character string followed byfive values.The last line will contain the word"Totals" followed by five values and will be separatedfrom the previous output line by a blank line.Theoutput will be preceded by the title lines:Computation of Weekly PayGross Fed State Soc.Net" A normal output line will look likeAllan Mackenzie 285.00 40.50 6.75 14.25 223.50" Erroneous data will produce error messages of the formInvalid hours for Robert A.VernerInvalid rate for Simon J.C.W.SurryInvalid dependents for T.Guy Rimmer" These messages will appear if the values read are notwithin the given limits.A single employee data linewith erroneous data can generate from one to threeerror messages.The erroneous data have to becorrected and resubmitted.To run the program, enter the payroll data in filePayroll.data and execute Payroll.Step 7 Program MaintenanceProgram maintenance is not directly part of the original implementationprocess, but needs special emphasis.All activities that occur after a programfirst becomes operational are part of the program maintenance.Many largeprograms have long lifetimes that often exceed the lifetime of the hardwarethey run on.Usually, the cost of program maintenance over the lifetime of aprogram will be greater than the total program development costs
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