RPG IV Overview

Cycle Programming

When

a system processes data,

it must do the processing in a partic

This

logical order is provided

by:

¹ The ILE RPG compiler

¹The program code

The logic the compiler supplies

programis calledcycle

the.When

you

let

the

 

 

compiler

provide

the

logic

for

your

programs,cycle programmingit is

called.

 

 

 

The

program

cycle

is

a series of steps that your program repeats un

condition

is

reached.

Depending

on

the

specifications

you

code,

the

 

or

may

not

use

each

step

in

the

cycle.

 

 

 

 

 

 

 

 

If

you

want to

 

have

files controlled by the cycle,

the

information

t

RPG

specifications

in

your source program need not specify when recor

files are

read.

The

compiler

supplies

the logical

order

for

these

op

some

output

operations,

when

your

source

program

is

compiled.

 

 

 

If you do not want

to

have

files

controlled by

 

the

cycle,

you

must

some

other

way,

 

either

by creating an

 

end-of-file

 

condition

by setting

record (LR) indicator, by creating a return condition by setting on th indicator, or by returning directly using the RETURN operation.

Note: No cycle code is generated for subprocedures or when NOMAIN is fied on the control specification.

Figure 1 shows the specific steps in the general flow of the RPG pro

Start

Perform

detail

calculations

Write heading and detail lines

Move fields

Get input

record

No

LR on

Yes

End of

program

Perform

total

calculations

Write total output

Figure 1. RPG Program Logic Cycle

.1/ RPG processes all heading and detail lines (H or D in position output specifications).

4 ILE RPG for AS/400 Programmer's Guide

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IBM AS/400 manual Cycle Programming, The.When You Let Compiler Provide Logic For Your

AS/400 specifications

The IBM AS/400, now known as the IBM iSeries, is a midrange computer system that has been a cornerstone of enterprise computing since its introduction in 1988. Designed to provide a robust platform for business applications, the AS/400 is celebrated for its reliability, scalability, and integrated database capabilities.

One of the key features of the AS/400 is its Integrated Operating Environment, which blends hardware and software resources seamlessly. This integration allows businesses to execute diverse workloads, ranging from traditional applications to modern web-based services, all on a single platform. The operating system, OS/400 (now IBM i), offers a rich set of APIs and tools for developers, simplifying application development and management.

Another standout characteristic of the AS/400 is its built-in database, DB2 for i. This powerful relational database management system allows for efficient data handling and provides advanced features such as support for SQL, XML, and JSON, making it easier for businesses to manage their data and integrate it with other systems. The database's tight integration with the operating system enables high performance and security.

In terms of scalability, the AS/400 can accommodate small businesses as well as large enterprises, with the ability to support hundreds of users simultaneously. Its architecture allows for easy upgrades in hardware, meaning that organizations can scale their systems without replacing the entire infrastructure.

Security is another critical attribute of the AS/400. With a sophisticated security model, it offers built-in user authentication, access control, encryption, and auditing capabilities to protect data and applications from unauthorized access.

The AS/400 also supports multiple programming languages, including RPG, COBOL, Java, and PHP, giving organizations the flexibility to choose the development tools that best fit their needs. This diversity helps maintain legacy applications while also developing new ones that leverage modern technologies.

Moreover, the platform supports both traditional green-screen interfaces and modern graphical user interfaces, allowing organizations to transition smoothly into contemporary user experience paradigms.

Overall, the IBM AS/400 stands out as a resilient, flexible, and secure computing platform that enables organizations to effectively manage their business operations, streamline processes, and adapt to changing market demands. Its unique combination of integrated features and capabilities ensures that it remains relevant in today's fast-paced technology landscape.