Prefer virtual function to casting

Reason

A virtual function call is safe, whereas casting is error-prone. A virtual function call reaches the most derived function, whereas a cast might reach an intermediate class and therefore give a wrong result (especially as a hierarchy is modified during maintenance).

Example

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Enforcement

See C.146 and ???

C.over: Overloading and overloaded operators

You can overload ordinary functions, function templates, and operators. You cannot overload function objects.

Overload rule summary:

• C.160: Define operators primarily to mimic conventional usage
• C.161: Use non-member functions for symmetric operators
• C.162: Overload operations that are roughly equivalent
• C.163: Overload only for operations that are roughly equivalent
• C.164: Avoid implicit conversion operators
• C.165: Use using for customization points
• C.166: Overload unary & only as part of a system of smart pointers and references
• C.167: Use an operator for an operation with its conventional meaning
• C.168: Define overloaded operators in the namespace of their operands
• C.170: If you feel like overloading a lambda, use a generic lambda