Initial Test (DO...WHILE) Loop

Syntax:

do while $\langle logical\_expr\rangle$
   $\langle exec\_stmts\rangle$ 
end do

The ession is evaluated at the beginning of every iteration; the loop executes only if it holds .TRUE. Clearly, the operands of the ession need to be modified during execution (otherwise the loop will either not execute or continue forever). Initial test loops are standard in most programming languages and have numerous applications.

The DO...WHILE LOOP can be replaced with the functionally equivalent construction: DO; IFEXIT ... END DO.