#include <iostream>
    #include <vector>
 
    using namespace std;
 
    class Foo {
 
    public:
      Foo() {}
      virtual ~Foo() {}
      Foo(const Foo&){cout << "constructed by lvalue reference." <<endl; }
      Foo(Foo&){cout << "constructed by non-const lvalue reference." <<endl; }
      Foo(Foo&& ) noexcept {cout << "constructed by rvalue reference." << endl; }
    };
 
 
    int main(int argc, char **argv, char** envp)
    {
      vector<Foo> vf;
      cout << "Insert a temporary.  One move:" << endl;
      vf.emplace_back(Foo{});
      cout << "Insert a temporary(2).  Two moves:" << endl;
      vf.emplace_back(Foo{});
      cout << "Resize with temporary(3).  Two moves:" << endl;
      vf.resize(10);
 
      vector<Foo> vf2;
      Foo foo{};
      cout << "Insert a variable.  One copy:" << endl;
      vf2.emplace_back(foo);
      cout << "Insert a variable(2).  One move, one copy:" << endl;
      vf2.emplace_back(foo);
      cout << "Resize with variable(3).  Two moves:" << endl;
      vf2.resize(10);
 
      vector<Foo> vf3;
      cout << "Insert a nothing.  No copy or move:" << endl;
      vf3.emplace_back();
      cout << "Insert a nothing(2).  One move:" << endl;
      vf3.emplace_back();
      cout << "Resize with nothing(3).  Two moves:" << endl;
      vf3.resize(10);
    }
 

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