Serin serout problem

[skimask]

ZeroF: ' cases when zero celcius and 0 Fahrenheit

end

You do realize that 0C is not 0F right?
0C = 32F
0F = -17.78C

Maybe it would be easier (if you really need to display both C and F) if you'd convert your initial celsius reading from the serin statements over to the Kelvin scale (0C = 273K, 0K = -273C), add in the correction factors, and then convert them back, taking into account the + and - as needed right before displaying the final numbers