# QTIPS - FOR/NEXT variables

Published By | Date | Version | Knowledge Level | Keywords |
---|---|---|---|---|

Sprezzatura Ltd | 01 JUN 1992 | 2.12+ | EXPERT | FOR, NEXT, STEP |

Tony McDowell writes - "The documentation (page N4.73) states that "start", "end" and "step" must be integers. A little experimentation might suggest that in fact any decimal fractions can be used for these variables. Don't be fooled. If STEP is a decimal fraction then anomalous results can occur. Specifically, it seems that the "even-ness" of the bound and step variables is critical. My tests show that if step and the lower and upper bounds are "even" decimal fractions then the FOR/NEXT loop will incorrectly terminate when step is equal to "end" rather than when it exceeds "end" (or underflows if step is negative)."

* This one is bad - it won't hit -2.0 A = 2 ; B = -2 For I = A To B Step -0.2 ; Call Msg("I = " : I) ; Next * This one is OK A = 1 ; B = -1 For I = A To B Step -0.2 ; Call Msg("I = " : I) ; Next * This one OK A = 2 ; B = 4 For I = A To B Step -0.5 ; Call Msg("I = " : I) ; Next * This one is bad - it won't hit 4.0 A = 2 ; B = 4 For I = A To B Step -0.4 ; Call Msg("I = " : I) ; Next

* NB Version 2.12 MSG used above!

(Volume 4, Issue 2, Page 5)