c++ - Adding Elements to std::vector of an abstract class -

i want store objects of classes derived common interface (abstract class) in std::vector of abstract class. vector should filled in loop , call constructor of class , push created object vector.

as understand, in case of abstract class can store pointers class, need push_back pointers of derived classes. however, not sure scope of these newly created objects.

please, have @ code below. code compiles , works fine questions are:

a) objects guaranteed exist in second for-loop in main function? or might cease existing beyond scope of loop in created?

b) objects' destructors called or might there memory leaks?

#include<vector> #include<iostream> class interface {     public:     interface( int y ) : x(y) {}     virtual ~interface() {}     virtual void f() = 0;     int x;   };  class derived_a : public interface {     public:     derived_a( int y ) : interface(y) {}     void f(){ return; } };  class derived_b : public interface {     public:     derived_b( int y ) : interface(y) {}     void f(){ return; } };   int main() {     std::vector<interface*> abstractobjects;     int n = 5;     for(int ii = 0; ii < n; ii++ )     {         abstractobjects.push_back( new derived_a(ii) );         abstractobjects.push_back( new derived_b(ii) );     }      for(int ii = 0; ii < abstractobjects.size(); ii++ )     {         abstractobjects[ii]->f();         std::cout << abstractobjects[ii]->x << '\t' << std::endl;     }       for(int ii = 0; ii < abstractobjects.size(); ii++ )     {         delete abstractobjects[ii];     }      return 0; } 

this perfect case smart pointers. can store pointers in unique_ptr raii type. when unique_ptr goes out of scope autmaticlly delete memory you.

    //...     std::vector<std::unique_ptr<interface>> abstractobjects;     int n = 5;     for(int ii = 0; ii < n; ii++ )     {         abstractobjects.push_back( std::make_unique<derived_a>(ii) );         abstractobjects.push_back( std::make_unique<derived_b>(ii) );     }      for(auto & e : abstractobjects)  // ranged based loop     {         e->f();         std::cout << e->x << '\t' << std::endl;     }     // no need here.  vector rid of each unique_ptr , each unique_ptr delete each pointer     return 0; }