To select one of any number of choices, use the SELECT/WHEN/OTHERWISE/END instruction. In a flowchart it appears as follows: The language processor scans the WHEN clauses starting at the beginning until it finds a true expression. After it finds a true expression, it ignores all other possibilities, even though they might also be true.

Rexx Tutorial - There are two types of conditional instructions. IF/THEN/ELSE can direct the execution of an exec to one of two choices. SELECT/WHEN/OTHERWISE/END can direct the execution to one of many choices.

REXX expressions can be used in FORM.CALC, FORM.CONDITIONS and FORM.COLUMNS (Column Definition). A valid REXX expression that can be reduced to a 0 or 1. Typically contains a REXX comparative operator. The @IF function tests the comparison and if the result is 1, the expression following the function is evaluated and the results are returned.

All loops, regardless of the type, begin with the DO keyword and end with the END keyword. The simplest loop tells the language processor to repeat a group of instructions a specific number of times using a constant following the keyword DO. SAY 'Hello!' When you run this example, you see five lines of Hello!. Hello!

2008年8月28日 · So turn to batch, with one truth in your head : REXX is not the best for IO, for reading huge file. You have to know that. So ( don't speak of "browse mode" ) your job has …

2006年8月31日 · Every time you have a "THEN DO", you must have an END to close the "THEN DO". You also need an "END" to close the SELECT. If none of the whens are true, the program will execute the commands after "otherwise". If otherwise is missing, an error will result. The DO is not part of the select statement.

The END instruction signals the end of the SELECT instruction. o If expression1 is false, expression2 is tested. Then, if expression2 is true, instruction2 is run and processing continues with the instruction following the END. o If, and only if, all of the specified expressions are false, then processing continues with the instruction ...

2025年1月21日 · In this post, we will explore the syntax of conditional statements, discuss their variations, and provide practical examples to illustrate their use. By the end, you’ll have a clear understanding of how to harness the power of conditional logic to elevate your REXX programming skills. Let’s get started!

After any of the WHEN conditions is met, the program stops checking, executes a line of code, and skips to the end. You can allow more complex functionality by using DO/END blocks. say "Would you like to convert feet to meters or meters to feet?" say "Type M to enter a number of meters or F to enter a number of feet." when choice = "M" then do.

To execute more than one instruction after the then or else, use a do-end pair, such as: then do . . . end or else do . . . end. To code a branch with no instructions, use the nop instruction.