UNTILU.

The part of the REPEATUNTIL structure which signifies its end.

You can use a REPEATUNTIL loop to repeat a set of program instructions until some condition is met.

If the condition associated with the UNTIL statement is never met, the loop will execute for ever. (At least, until Escape is pressed or some other error occurs).

The following example will continually ask for a number and print its square. The only way to stop it is by pressing Escape or forcing a 'Too big' error.

10 z=1
20 REPEAT
30   INPUT "Enter a number " num
40   PRINT "The square of ";num;" is ";num*num
50 UNTIL z=0

Since the result of the test z=0 is always false, we can replace z=0 with FALSE. The program now becomes:

20 REPEAT
30   INPUT "Enter a number " num
40   PRINT "The square of ";num;" is ";num*num
50 UNTIL FALSE

This is a much neater way of unconditionally looping than using a GOTO statement. The program executes at least as fast and the section of program within the loop is highlighted by the indentation.

See the keyword REPEAT for more details on REPEATUNTIL loops. See the Variables sub-section for more details on Boolean variables and the keyword AND for logical tests and their results.

Syntax

UNTIL <t-cond>

Associated Keywords