Item 37: Never Redefine a Function's Inherited Default Parameter Value

Because default parameter values are statically bound, even for virtual functions (surprise!).

• Meaning, you may invoke a virtual function defined in derived class with default parameter value from a base class.

So if you really really want to use default parameter for a virtual function, consider use NVI as an alternative:

• Define a non-virtual public function with default parameter
• Define a virtual private function without default parameter
• The public function calls the private function, passing the default parameter value
  • Because you should not redefine non-virtual function, the default parameter is not redefined
  • Because the (private) virtual function does not have default parameter, you don’t have to worry about redefining default parameter when you redefine the virtual function
  • So everyone is happy!