More subroutine sandwich. (book reviews) Stephen Gray.

More Subroutine Sandwich, by John P. Grillo and J.D. Robertson. John Wiley & Sons, Inc., New York. 270 pages paperback $12.95. 1983.

This is the second of two manuals of Extended Basic subroutines useful in reducing the time requirerd to build programs. The 15 chapters are divided into three parts: Suggestions to the Reader (How to Use This Book. How to Use the Subroutines), Subroutines, and Mother Programs.

The eight subroutine chapters cover Date Processing (Julian Date, Reverse Day of the Year, etc.), Word Processing (Buffer Fill, Text Justify, etc.), Cryptography (Phrase Key Code, Rail-Fence Code, etc.), Mathematics (Binary-to-Decimal Conversion, Horner's Method, etc.), Table Management (Insertion Sort, Quicksort, etc.), Statistics (Rank, Permutations, etc.), Table Lookup and Utilities (Interpolation Search, Shuffle, etc.), and Business (Straight-Line Depreciation, Declining-Balance Depreciation, etc.).

Each of the 36 subroutines covers four pages, and includes a description of how it works, source reference, listing, list of variables, notes on modifications and special features, a program that incorporates it, and a run.

Each of the last five chapters contains a mother program that "illustrates the real-life applications of many of the subroutines": Resort Time-Sharing Weeks, Text in Adjacent Columns, File Protection, Chebyshev Polynomial Plotter, and Probability of One Pair in Poker.

The title of the book comes from the authors considering the first and third parts (suggestions and mother programs) to be the slices of bread, and the subroutines to be the filling: the cover shows a juicy hamburger.

There have been many books of "useful" programs; this is one of the very few to provide such programs as building-block subroutines, to be assembled into whatever the reader has in mind. And it is one of the very best, packing many useful ideas into a handy volume. Although "intended primarily for the TRS-80 Basic programmer, it is appropriate for any othere programmer as well."

The only catch is that, to have the widest choice of subroutines, you'll have to buy the authors' first book, Subroutine Sandwich, also $12.95. with almost exactly the same chapter headings and thus the same types of subroutines among the 36 provided. The five mother programs are Annotated Calendar, Binary Addition Drill and Practice, Tea Selection, Linear Interpolation, and Monthly Sales Data Report.

Review Grade: B