Adding derived class object to vector<unique_ptr> of base class-CodePudding

So in my code I'm trying to add unique_ptr to objects from derived class to vector of base class. I get this error:

E0304 no instance of overloaded function "std::vector<_Ty, _Alloc>::push_back [with _Ty=std::unique_ptr<Organism, std::default_delete<Organism>>, _Alloc=std::allocator<std::unique_ptr<Organism, std::default_delete<Organism>>>]" matches the argument list

The code of base class (if you need more let me know, trying to put as little code as possible):

vector<unique_ptr<Organism>>  World::generate_organisms(int act_level)
{
    vector<unique_ptr<Organism>> organism_list = get_vector();
    coordinates sheep_pos(10, 2);
    //getting error in next line
    organism_list.push_back(make_unique<Sheep>(sheep_pos, *this));

    return organism_list;
}

Code of the derived class:

.h file

class Sheep : Organism
{
    Sheep( coordinates organism_pos, World* world);
};

.cpp file

Sheep::Sheep( coordinates organism_pos, World* act_world)
    :
    Organism(organism_pos, act_world)
{
    this->armor = 0;
    this->damage = 2;
    this->health = 10;
    this->vigor = 10;
}

CodePudding user response：

Similar to how the default member visibility of class is private, inheritance is also private unless otherwise specified. You need to inherit from Organism publicly so that std::unique_ptr is able to see and perform the conversions you expect.

class Sheep : public Organism {
public:
    Sheep( coordinates organism_pos, World* world);
}

Your constructor also needs to be public so that std::make_unique can see and use it.