How to force a call to a const qualified function overload?

Question

I'm trying to call const function inside a class, but a non-const function with the same name exists.

Note: I can't just change names.

class MyQuestion {  void fun()  {    cout<<"a";   }   void fun()const  {     cout<<"b";   }   void call()  {    fun();//<how to call fun() const?  } }; 

Answer 1

Option #1:

Call that function through a pointer to a const qualified type:

void call() {     static_cast<const MyQuestion*>(this)->fun();     //          ~~~~^ } 

c++11:

void call() {     const auto* that = this;     //~~^     that->fun(); } 

c++17:

void call() {     std::as_const(*this).fun();     //   ~~~~~~~^ } 

Option #2:

Make the calling function a const-qualified one:

void call() const //          ~~~~^ {     fun(); } 

DEMO