The WHILE statement marks the beginning of a WHILE loop or  qualifies  the
  execution of another statement.

  Examples

  X = 1
  WHILE X<100
      X = X + SQR(X)
  NEXT

  X% = X% + 1% WHILE X% > 100%

1  –  Syntax

  Conditional:

      WHILE cond-exp
            [ statement ]...
      NEXT

  Statement Modifier:

      statement WHILE cond-exp