// This is an example of duck typing.
//
// A vector requires that its stored type be copyable, both via copy ctor and
// assignment operator, but the class that we’re storing is not copyable.
//
// Observe what a splendid error message is produced!

#include <vector>

class Mom {
  public:
    Mom() = default;				// I like the default ctor.
    Mom(const Mom &) = delete;			// You can’t change Mom!
    Mom& operator=(const Mom &) = delete;	// You can’t change Mom!
};

int main() {
    std::vector<Mom> v;
    Mom helen;
    v.push_back(helen);
    return 0;
}