Do...Loop
DO and LOOP cause code to be executed while a certain condition evaluates to true, or until a certain condition evaluates to true. The "while" and "until" parts of this expression can be located either in the "DO" statement or the "LOOP" statement. The following form is good for cases when you want a loop that always executes once and then only loops back as long as a condition is met. It will continue looping back and executing the code as long as the booleanExpr evaluates to true.
    'execute the code inside this loop at least once
    do
        'code in here
    loop while booleanExpr
You can also use the UNTIL keyword to reverse the logic of the expression:
    'execute the code inside this loop at least once
    do
        'code in here
    loop until booleanExpr

