### inRange

Checks if the given number falls within the given range. 

Use arithmetic comparison to check if the given number is in the specified range.
If the second parameter, `end`, is not specified, the range is considered to be from `0` to `start`.

```js
const inRange = (n, start, end=null) => {
  if(end && start > end) end = [start, start=end][0];
  return (end == null) ? (n>=0 && n<start) : (n>=start && n<end);
}
// inRange(3, 2, 5) -> true
// inRange(3, 4) -> true
// inRange(2, 3, 5) -> false
// inrange(3, 2) -> false
```