I just learned about while statements and get why you place them around
inputs for validation, but I'm a little lost on exactly where to place
it with what condition in this program where the number of fat grams
exceeds the total number of calories so that it loops back and asks you
the two questions again instead of just saying The calories or fat grams
were incorrectly entered. Any idea's?
thx
while cal <=0:
#Prompt for calories
cal = input("Please enter the number of calories in your food: ")
if cal <=0:
print "Error. The number of calories must be positive."
#Prompt for fat
fat = input("Please enter the number of fat grams in your food: ")
if fat <=0:
print "Error. The number of fat grams must be positive."
#Calculate calories from fat
calfat = float(fat) * 9
#Calculate number of calories from fat
caldel = calfat / cal
#change calcent decimal to percentage
calcent = caldel * 100
#evaluate input
if calfat > cal:
print "The calories or fat grams were incorrectly entered."
elif calcent > 0 and calfat < cal:
if caldel <= .3:
print "Your food is low in fat."
elif caldel >= .3:
print "Your food is high in fat."
#Display percentage of calories from fat
print "The percentage of calories from fat in your food is %",
calcent
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