std::set containing std::unique_ptr

trySet.cpp

// C++ 14
#include <iostream>
#include <memory>
#include <set>

// template specialization
template<typename T> struct std::less<std::unique_ptr<T>> {
  bool operator()(const std::unique_ptr<T>& a, const std::unique_ptr<T>& b) const {
    return *a < *b;
  }
};

int main ()
{
  std::set<std::unique_ptr<int>> st;

  for ( auto element : {1, 3, 1, 5, 13, 8, 2} ) {
    st.insert(std::make_unique<int>(element));
  }

  for ( auto& element : st ) {
    std::cout << *element << " ";
  } std::cout << "\n";

  return 0;
}