// From: http://en.cppreference.com/w/cpp/language/const_cast

#include <iostream>
 
struct type {
  type() {i=3;}
  void m1(int v) const {
    // this->i = v;                 // compile error: this is a pointer to const
    const_cast<type*>(this)->i = v; // OK as long as the type object isn't const
  }
  int i;
};
 
int main() {
  int i = 3;                    // i is not declared const
  const int& cref_i = i; 
  const_cast<int&>(cref_i) = 4; // OK: modifies i
  std::cout << "i = " << i << '\n';
 
  type t; // note, if this is const type t;, then t.m1(4); is UB
  t.m1(4);
  std::cout << "type::i = " << t.i << '\n';
 
  const int j = 3; // j is declared const
  int* pj = const_cast<int*>(&j);
  *pj = 4;         // undefined behavior!
  
  void (type::*mfp)(int) const = &type::m1; // pointer to member function
//  const_cast<void(type::*)(int)>(mfp); // compiler error: const_cast does not
                                         // work on function pointers
}