# 做什么

/* This is a well defined DO WHILE loop that will run as long as i is lower than 10*/
DEFINE VARIABLE i AS INTEGER     NO-UNDO.
DO WHILE i < 10:
i = i + 1.
END.

DISPLAY i. // Will display 10


DEFINE VARIABLE i AS INTEGER     NO-UNDO.
DO WHILE TODAY = DATE("2017-02-06") AND RANDOM(1,100) < 99:
i = i + 1.
END.

MESSAGE i "iterations done" VIEW-AS ALERT-BOX.


/* Oops. Didnt increase i. This will run forever... */
DEFINE VARIABLE i AS INTEGER     NO-UNDO.
DO WHILE i < 10:
i = 1.
END.