local n = 0
local sum = 0
while true do
    io.write("Enter integral rainfall (99999 to quit): ")
    local i = tonumber(io.read())
    if !(i and i % 1 == 0) then
        print("Must be an integer, try again.")
        continue
    end
    if i == 99999 then break end
    ++n
    sum += i
    print($"  The current average rainfall is {sum / n}")
end