mm to inches

oldhippy

I am trying to convert mm to inches using a BS2. the BS2 rounds off. Any way to get tenths of an inch out of the BS2?

kwinn

A mm is 0.03936996 inches. or approximately 0.04 inches so if you multiply the mm by 2.54 (or do successive adds) you can get tenths of an inch without the decimal.

If you are doing this in floating point multiply the mm by 10 or 100 and divide by the same amount after the conversion is done.

Tracy Allen

to tenths:
inch10 = mm ** 25802 ' good up to 65536mm
to hundredths:
inch100 = mm * 10 ** 25802 ' good up to 6553mm
to thousandths
inch1000 = mm * 100 ** 25802 ' good up to 655mm

example
mm = 25
inch1000 = 984 ' meaning 0.984 inch true value 0.984251968505

** 25802 using the PBASIC ** operator.is equivalent to 25802/65536 = ~0.3934

Duane Degn

I gave this a try before seeing Tracy's post.

I'm very rusty in PBASIC but this was the output when entering 88 mm.

Please enter millimeters: 88
88 mm = 3.5 in
Please enter millimeters:

Here's the program:

' {$STAMP BS2}
' {$PBASIC 2.5}


CONVERSION      CON     254
ROUNDING        CON     127
SCALE100        CON     100


millimeters     VAR     Word
inches          VAR     Word
tenthsOfInches  VAR     Word


Main:
  DO
    DEBUG CR, "Please enter millimeters: "     ' prompt user
    DEBUGIN NUM millimeters     ' retrieve number
    tenthsOfInches = ((millimeters * SCALE100) + ROUNDING) / CONVERSION
    inches = tenthsOfInches / 10
    tenthsOfInches = tenthsOfInches - (10 * inches)  ' I don't remember how to do modulus with BS.
    DEBUG DEC millimeters, " mm = ", DEC inches, ".", DEC tenthsOfInches, " in"


    PAUSE 1000                          ' wait one second
  LOOP                                  ' repeat forever

Unfortunately the word size variables in PBASIC don't lend themselves to doing math with large numbers. I bet a much better program could be written using the tricks Tracy showed us.

oldhippy

Thanks i'll try it tomorrow