| Avoid overloading the comma operator (','), operator AND ('&&'), and operator OR ('||'). |
| Always write operations, that are normally equivalent, to be equivalent when overloaded. |
| Ensure that overloaded binary operators have expected behaviour. |
| Make binary operators non-members to allow implicit conversions of the left hand operand. |
| When overloading the subscript operator ('operator[]') implement both const and non-const versions. |