null created by benoxoft - https://repl.it/Kgxj/1

Kgxj-1.cpp

#include <iostream>
using namespace std;

class Widget {
public:
  Widget(int i, bool b);      // ctors not declaring
  Widget(int i, double d);    // std::initializer_list params
};

Widget::Widget(int i, bool b) {
  cout << "Constructeur #1" << endl;
  cout << i << endl;
  cout << b << endl;
}

Widget::Widget(int i, double d) {
  cout << "Constructeur #2" << endl;
  cout << i << endl;
  cout << d << endl;
}

int main() {
Widget w1(10, true);          // calls first ctor
Widget w2{10, true};          // also calls first ctor
Widget w3(10, 5.0);           // calls second ctor
Widget w4{10, 5.0};           // also calls second ctor  
}