Python

add an outside the loop to avoid the division by zero and tell the user that you can$$t compute an average without data.

def main$()$:

total $=0$

count $=0$

moreItems $=$ True

while moreItems:

price $=$ float$($input$(\text{'}$Enter price of item $(0$ when done$)$: $\text{'}))$

if price $!=0$:

count $=$ count $+1$

total $=$ total $+$ price

print$(\text{'}$Subtotal: $$\text{'},$ total$)$

else:

moreItems $=$ False

average $=$ total $/$ count

print$(\text{'}$Total items:$\text{'},$ count$)$

print$(\text{'}$Total $$\text{'},$ total$)$

print$(\text{'}$Average price per item: $$\text{'},$ average$)$

main$()$