REXX - Program Flow
Duration
3 hours
Overview
In this course you will see how the normal sequential flow of a REXX program can be altered so that code is skipped, or repeated. Instructions used to evaluate and act on a value if it is true, are discussed, while details on methods used to loop instructions are explained in depth.
Audience
Personnel responsible for writing or maintaining REXX programs.
Prerequisites
Successful completion of the Interskill REXX – General REXX Instructions course, or equivalent knowledge.
Objectives
After completing this course the student should be able to:
- Use conditional processing to perform actions while a value is true
- Explain how loops are coded in a REXX program
Course Content
Conditional Processing
IF/THEN/ELSE Construct Flow
Benefits of Using IF/THEN/ELSE
Nesting IF Statements
Common IF/THEN/ELSE Coding Errors
Using the No Operation Instruction
Using the SELECT/WHEN/OTHERWISE Construct
Common SELECT Errors
Looping
Simple DO Processing
Types of Looping
Repetitive DO Loops
Controlled Repetitive Loops
DO FOREVER
DO WHILE
DO UNTIL
Compound DO Structures
LEAVE Instruction
Altering the Flow with the ITERATE Instruction
Escaping from an Infinite DO Loop
Common DO Coding Errors