Table of Temperatures... Help

[buran]

Also, not sure if you need to do this but usually one would check the user input, e.g. what will happen if user instead of number, input some letters.
Once you take both min. and max. Celsius (btw. note the spelling :)) values, what will happen if min (as entered by the user) is actually greater than max (again - the one entered by the user)?
Do you need to take care of cases like these or simply hope for correct user input?