- Test expects '//;\n1;2' to return 3
- Currently fails with FormatException
- Custom delimiter extraction is commented out
- Tries to parse '1;2' as single number, fails
- Test expects '1,2' to return 3
- Currently returns 1 (missing last element)
- Summation loop has off-by-one: for (i < length - 1)
- Expected: <3>, Actual: <1>
- Expected: <6>, Actual: <3>