I'm making a standard form calculator (e.g. 7 x 10^5) and I need help thinking of the best method to use.

I basically need the program to take the number/input (say 70000) and then see what multiple of 10 it divides by to give a number between 1 and 9. Like this;

If Input / 1 = 1 or 2 ... or 9 then

output = 0

elseif input / 10 = 1 or 2 ... or 9 then

output = 1

elseif input / 100 = 1 or 2 ... or 9 then

output = 2

(Then, if nothing satisfies...)

if input * 10 = 1 or 2 ... or 9 then

output = -1

I need it to do this and work it out for any size number. What's the best method for this? Some sort of array?

Thanks.