An In-Depth Review of RPG Programming: Historical Development and Key Features

1. RPG Programming Test One Review

2. Chapter One • RPG: Report Program Generator • Released in the early 60’s • RPGII – released with System/3 • RPGIII – 1970’s • RPG/400 – Release with the AS/400 • RPGIV - 1994 • Higher Level Language • Procedural Language

3. Chapter One • First released with a Fixed Logic Cycle • Uses Indicators • Built in variables with value of 0 or 1 • Now it is procedural • Program Variables – represents a location in the memory of the computer that can store data.

4. Chapter One • Printer Spacing Chart • Output Editing • Syntax errors: errors in your use of the rules of the language • Logic errors: errors in design • Debugging: discovering and correcting errors

5. Chapter One • Use SEU to enter source code • Compile the course code • Call the compiled object

6. Chapter Two • File Description Specifications (F Specs) • Identifies the files your program uses • Identifies how the files will be used • Recommended entries (F Prompt): • File Name • File Type • File Designation • File Format • Record Length • Device

7. Chapter Two • Input Specifications (I Specs) • Record Identification Entries (I Prompt) • File Name • Sequence • Field Description Entries (J Prompt) • Field Location • Decimal Positions • Field Name

8. Chapter Two • Calculation Specifications: Describes processing steps • Operation Code • Factor 2/ Extended Factor 2 (C or CX Prompt)

9. Chapter Two • Op Codes: • EXCEPT: Directs the program to output lines from the O Specs • READ: Retrieve the next sequential record • DOW: Do while loop, requires an ENDDO to signal the end of the loop • EVAL: Used to assign a value to a variable • RETURN: Returns control to the program that called.

10. Chapter Two • Output Specifications (O Specs) • Record Identification Entries (O Prompt) • File name • Type • Exception Name • Space and Skip Entries • Field Description Entries (P Prompt) • Field Name • Constants • End Position • Edit Codes

11. Chapter Two • Output Editing: Formatting output values • Edit Codes • Edit Words

12. Chapter Three • Definition Specifications (D Specs): used to define additional fields used in programming but are not from an input file. • Standalone Fields: • Numeric Literal • Character Literal • Figurative Constants • *BLANKS, *HIVAL, *ZERO, *ON, *OFF…

13. Chapter Three • Initial Value: Value field contains at programs start. • Data Types (p. 43) • Defining Constants: • Value never changes during processing • Defined with no specified length

14. Chapter Three • Data Structures: means of organizing multiple fields within a single section of contiguous portions of memory

15. Chapter Four • EVAL: Assigns a value to a field • Uses the Extended Factor 2 format • Supports the following arithmetic operators • + addition • - subtraction • * Multiplication • / Division • **Exponentiation • () Parentheses • <> Relational Symbols • AND OR Logical operators

16. Chapter Four • Truncation: loss of digits from the right/or left end of a result field • High order Truncation • Low order Truncation

17. Chapter Four • Determining Field Sizes: (See chart) • Rounding (Half Adjusting) • (H) • Result Decimal Position Rule • (R) • Line Continuation Character +

18. Chapter Four • Character assignment also works with the Eval Statement. • Can also assign values with figurative constants: (*Blanks, *Zero, etc..)

19. Chapter Four • Data Type Conversion • MOVE Operation: Value in Factor2 is copied to the result field, character by character from right to left. • MOVEL Operation: Value in Factor2 is copied to the result field, character by character from left to right.

20. Chapter Four • Built in Functions: • %ABS (Absolute Value) • %DIV (Divide, return Integer result) • %REM (Divide, return Remainder)