Table of Contents

Preface

Chapter 1: Introduction to Programming and RPG 
Chapter Overview 
Programming 
History of RPG 
Program Variables 
Data Files and the Data Hierarchy 
Programming Specifications 
The Program Development Cycle 
Program Entry and Testing 
Chapter Summary 
Terms 
Discussion/Review Questions 
Exercises 

Chapter 2: Getting Started 
Chapter Overview 
Specifications Forms in RPG 
Program Specifications for Example Program 
File Description Specifications 
Input Specifications 
Record Identification Entries 
Field Description Entries 
Output Specifications 
Record Identification Entries 
Field Description Entries 
Calculation Specifications 
Indicators and Calculations 
RPG Operations 
Internal Documentation 
The Completed Program
Output Editing 
Edit Codes 
Edit Words 
Chapter Summary 
Terms 
Discussion/Review Questions 
Exercises 
Programming Assignments 

Chapter 3: Arithmetic and Assignment Operations
Chapter Overview 
Numeric Literals and Fields 
Arithmetic Operations 
Numeric Truncation and Field Sizes 
Result Field Size for Addition 
Result Field Size for Subtraction 
Result Field Size for Multiplication 
Result Field Size for Division 
Rounding 
Effective Commenting on Calculations 
Putting It All Together 
Assignment Operations 
Character Literals 
Figurative Constants 
Chapter Summary 
Terms 
Discussion/Review Questions 
Exercises 
Programming Assignments 

Chapter 4: Top-Down, Structured Program Design 
Chapter Overview 
Structured Design 
Sequential Flow of Control 
Relational Comparisons 
Selection Operations 
IF and Page Overflow
Operations for Iteration 
Loops and Early Exits 
Unstructured Operations 
Top-Down Design 
Defining Subroutines 
Scope Terminators 
Control-Break Logic
Chapter Summary 
Terms 
Discussion/Review Questions 
Exercises 
Programming Assignments 

Chapter 5: Externally Described Files 
Chapter Overview 
The AS/400 Approach to Database Files 
Physical and Logical Files 
Introduction to DDS 
Defining Physical Files 
Data Types and Data Storage 
Defining Logical Files 
Simple Logical Files 
Record Selection/Omission 
Logical Files with Multiple-Record Formats 
Join-Logical Files 
Creating Database Files 
RPG Programming with Externally Defined Files 
Additional Database File Concepts 
Externally Described Printer Files 
Putting It All Together 
Chapter Summary 
Terms 
Discussion/Review Questions 
Exercises 
Programming Assignments

Chapter 6: File Access and Record Manipulation 
Chapter Overview 
Operations for Input Files 
Sequential Access 
Random Access 
Referencing Composite Keys 
Operations for Output Files 
Update Files and I/O Operations 
File and Record Locking 
I/O Errors 
Chapter Summary 
Terms 
Discussion/Review Questions 
Exercises 
Programming Assignments 

Chapter 7: Interactive Applications 
Chapter Overview 
Batch and Interactive Programs 
Display Files 
Additional DDS Keywords 
File-Level Keywords 
Record-Level Keywords 
Field-Level Keywords 
Conditioning Indicators 
Interactive File Maintenance 
Screen Design and CUA 
Chapter Summary 
Terms 
Discussion/Review Questions 
Exercises 
Programming Assignments 

Chapter 8: Tables and Arrays 
Chapter Overview 
Tables 
Table Definition 
Compile-Time Tables 
Pre-Runtime Tables 
Table Look-Ups 
Two Related Tables 
Multiple Related Tables 
Range Tables 
Changing Table Values 
Arrays 
Runtime Arrays and Input Data 
Calculations with Arrays 
Using Arrays 
Array Look-Ups 
Indicators as Array Elements 
Output with Arrays 
Chapter Summary 
Terms 
Discussion/Review Questions 
Exercises 
Programming Assignments 

Chapter 9: Advanced Data Definition 
Chapter Overview 
Named Constants 
*LIKE DEFN (Field Definition) 
Data Structures 
Simple Data Structures 
Multiple-Occurrence Data Structures 
Initialization and Reinitialization of Variables 
File-Information Data Structures 
Program-Status Data Structures 
Error Handling and *PSSR 
Chapter Summary 
Terms 
Discussion/Review Questions 
Exercises 
Programming Assignments 

Chapter 10: Interactive Programs: Advanced Techniques
Chapter Overview 
Subfiles 
Subfile Record Formats 
Subfile Control-Record Formats 
Loading the Entire Subfile 
Loading the Subfile a Page at a Time 
Subfiles and Change 
Uses of Subfiles 
On-Line Help 
Chapter Summary 
Terms 
Discussion/Review Questions 
Exercises 
Programming Assignments 

Chapter 11: Byte- and Bit-Level Operations 
Chapter Overview 
Field Character Inspection 
Field Character Manipulation 
Using Arrays for String Manipulation 
Working with Bits 
Chapter Summary
Terms 
Discussion/Review Questions 
Exercises 
Programming Assignments 

Chapter 12: Interprogram Communications 
Chapter Overview 
Modular Programming 
Calling Programs 
Passing Data Between Programs 
Calling QCMDEXC 
Data Areas 
Data-Area Data Structures 
Using *NAMVAR DEFN 
Chapter Summary 
Terms 
Discussion/Review Questions 
Exercises 
Programming Assignments 

Chapter 13: Looking Backward: RPG II 
Chapter Overview 
RPG II: An Initial Look 
RPG's Fixed-Logic Cycle 
The Fixed-Logic Cycle and Control Breaks 
Decisions in RPG II 
Resulting Indicators and Arithmetic 
Iteration and RPG II 
Chapter Summary 
Terms 
Discussion/Review Questions 
Exercises 
Programming Assignments 

Chapter 14: Looking Forward: RPG IV 
Chapter Overview 
Introduction to RPG IV 
Modifications to File Specifications 
Modifications to Extension Specifications 
Introducing Definition Specifications 
Modifications to Input Specifications 
Modifications to Calculation Specifications 
Modifications to Output Specifications 
Putting It All Together 
Pseudocode for Invoice Program 
Chapter Summary 
Terms 
Discussion/Review Questions 
Exercises 
Programming Assignments 

Appendix A: Developing Programs on the AS/400 
The Programmer Menu 
Programming Development Manager (PDM) 

Appendix B: Source Entry Utility (SEU) 
SEU Overview 
Using Prompts 
Working Within the Edit Display 
Function Keys in SEU 
SEU's Command Line 
Working with a Split Screen 
Exiting SEU 

Appendix C: Program Testing and Debugging 
Syntax Errors 
Logic Errors 
Runtime Errors 
Diagnosing Abends 
Diagnosing Infinite Loops 
Output Errors 
Detecting Output Errors 
Correcting Output Errors
Debug 
Breakpoints 
Trace Commands 

Appendix D: Data Files 
Case 1: CompuSell 
Case 2: Wexler University 
Case 3: GTC, Inc. 
Miscellaneous Files 

Appendix E: RPG IV and RPG/400 

Chapter 1 Modifications 
Chapter 2 Modifications 
Chapter 3 Modifications 
Chapter 4 Modifications 
Chapter 5 Modifications 
Chapter 6 Modifications 
Chapter 7 Modifications 
Chapter 8 Modifications 
Chapter 9 Modifications 
Chapter 10 Modifications
Chapter 11 Modifications
Chapter 12 Modifications
Chapter 13 Modifications
Glossary 
Index 

Judy Yaeger is an associate professor emerita in the business information systems department at Western Michigan University, Kalamazoo, Michigan. She earned her PhD in experimental psychology and an MBA with an emphasis in computer information systems. Judy taught computer programming, including RPG, for more than 15 years at both the community college and university levels before retiring. She is currently living in Belize, operating a nature center and lodging facility for budget travelers.