The prototype of the While..do statement is
While Expression Do Statement;This will execute Statement as long as Expression evaluates to True. Since Expression is evaluated before the execution of Statement, it is possible that Statement isn't executed at all.
Statement can be a compound statement.
Be aware of the fact that the boolean expressions Expression1 and Expression2 will be short-cut evaluated. (Meaning that the evaluation will be stopped at the point where the outcome is known with certainty)