411 REFERENCE · Wikibooks
Rexx Programming/How to Rexx/if
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The if conditional construct allows a /statement/ or /block/ of code to be conditionally executed based on the result of a boolean expression. The branch within the condition, only gets executed if the expression evaluates to a true value. The if condition its simplest form is:
if CONDITION then STATEMENT
For example:
if guess = 6 then
say "Wow! That was a lucky guess."
There is no endif cocomponent
Note that rexx programming language syntax does not utilize endif as a syntactical cocomponent. The endif placed in a comment in example below are for cosmetic purposes only for aiding indentation. These comments are ignored by the rexx interpreter.
if guess = 6 then
say "Wow! That was a lucky guess."
else
say "Sorry! That was not the right number."
/* endif */
Using the do construct to conditionally execute a branch containing more than one statement
In order to conditionally execute more than one statement within a conditional branch, it is necessary to enclose the statements within a do and end block:
if guess = 6 then
do
say "Wow! That was a lucky guess." /* Multiple statements in a do block */
prize = 30000
end
Nested conditional constructs
It is possible to created nested if structures:
if age > 79 then
say "Wow! You are so old that you are almost antique!"
else
if age >=65 then
say "You are a pensioner"
else
if age > 21 then
say "You have the key to the door"
else
say "You are just a youngster"
/* endif */
/* endif */
/* endif */