Check if a number is divisible by 3

Question

I need to find whether a number is divisible by 3 without using `%`, `/` or `*`. The hint given was to use `atoi()` function. Any idea how to do it?

Accepted Answer

Subtract 3 until you either

a) hit 0 - number was divisible by 3

b) get a number less than 0 - number wasn't divisible

-- edited version to fix noted problems

```
while n > 0:
    n -= 3
while n < 0:
    n += 3
return n == 0
```

Solution