Rexx - do-until Loop

The do-until loop is a slight variation of the do while loop. This loop varies in the fact that is exits when the condition being evaluated is false.

Syntax

The syntax of the do-until statement is as follows −

do until (condition) 
   statement #1 
   statement #2 
   ... 
end

The do-until statement is different from the do-while statement in the fact, that it will only execute the statements until the condition evaluated is true. If the condition is true, then the loop is exited.

Flow Diagram

The following diagram shows the diagrammatic explanation of this loop.

The key thing to note is that the code block runs till the condition in the do-until evaluates to false. As soon as the condition evaluates to true, the do loop exits.

The following program is an example of a do-until loop statement.

Example

/* Main program */ 
j = 1 

do until (j <= 10) 
   say j 
   j = j + 1 
end

The output of the above code will be −

1