c++ - How can I return unique_ptr from factory method? -

i have few classes heroes extended abstract class warrior:

enum warrior_id { infantryman_id=0, archer_id, horseman_id };  class warrior {   public:     virtual void info() = 0;     virtual ~warrior() { }     static unique_ptr<warrior> createwarrior( warrior_id id ); };  class infantryman: public warrior {   public:     void info()     {       cout << "infantryman" << endl;     } };  class archer: public warrior {   public:     void info()     {       cout << "archer" << endl;     } };  class horseman: public warrior {   public:     void info()     {       cout << "horseman" << endl;     } }; 

and factory method, returns specific character:

unique_ptr<warrior> warrior::createwarrior( warrior_id id ) {     unique_ptr<warrior> p;     switch (id)     {         case infantryman_id:             p = new infantryman(); //this doesn't work             break;         case archer_id:             p = new archer(); //this doesn't work             break;         case horseman_id:             p = new horseman(); //this doesn't work             break;         default:     }    return p; }; 

how can return unique_ptr specific character without using make_unique ?

std::unique_ptr's pointer constructor explicit, need

p = std::unique_ptr<warrior>{new infantryman()}; 

alternatively, use reset() member function:

p.reset(new infantryman()); 

as noted in comments, don't need declare local variable p , modify it. can return directly switch block:

    case infantryman_id:         return std::unique)ptr<warrior>{new infantryman{}};     case archer_id:         return std::unique)ptr<warrior>{new archer{}}; 

and on.