Mine

#include <iostream>using namespace std;class NoParameter{  NoParameter() {}};template<typename T>struct CountIfUsed{    enum { value = 1 };};template<>struct CountIfUsed<NoParameter>{    enum { value = 0 };};template<  typename T         , typename P1 = NoParameter         , typename P2 = NoParameter>struct CountParameters{    enum    { value =   CountIfUsed<P1>::value              + CountIfUsed<P2>::value    };};template<unsigned params>struct SwitchVisitable{};template<>struct SwitchVisitable<0>{  void foo() { cout << "zero args\n"; }};template<>struct SwitchVisitable<1>{  void foo(int x) { cout << "one arg\n"; }};template<>struct SwitchVisitable<2>{  void foo(int x, int y) { cout << "two args\n"; }};int main() {    SwitchVisitable<CountParameters<void, int>::value> obj;    obj.foo(1);}