I have no idea about how to use a "C" construct (array) in assembly, please be specific about it. As far as storing fractional numbers, let us say for the sake of arguments that we are talking about volts with up to 3 digits following the period. The way to handle it is to process internally in millivolts. You set 1000 somewhere in your storage and for every digit entered after the priod you divide this storage by 10. When 'enter' or whatever is pressed, you multiply the entered value by this number.

Happy hollidays,

Erik