"That's a problem for me. TrueBasic doesn't allow missing values in an input statement."

What if you were to input it as a string value and not a number? IF a$ = "" then val = 0. Even in XBasic I sometimes get creative with how I handle data. Remember that tidbit of code I emailed you on how I read characters in an image? Even though the actual values represented a binary number, it was a string array that held the data.

But actually, if you were reading in the output of Micheal's archive, the archive program is what should be making the assumptions and converting null inputs to the appropriate values.

"The problem is that zero means zero, so 3.5 0.0 would cause an error. The upper end can't be smaller than the lower end."

Again, just test for the case. If the upper bound is 0 (or even less than the lower value) then it assumes a maximum high value. I've always used 9.9 in my programs as the assumed upper bound.

And again, this should be handled in the archive interface and should ultimately not be a problem for you.

Brian