program start:
get temperature and windspeed from the user with the following conditions:
	- temperature is enterable in F or C
	- windspeed is enterable in mph or kph
	- -80 <= temp in F <= 121; -62 <= temp in C <= 49.5
	- 0 <= windspeed in mph <= 231; 0 <= windspeed in kph <= 378
determine and print windchill
program end: