CODEWITHSUNDEEP
c++inheritancetypestypeinfo
lenerdv
lenerdv

Reputation: 197

How to get the name of a derived class from a vector of base classes

So I have a vector of base classes and a couple bugs in my code, which means that I need to know which derived class is calling the polymorphic method:

class Base {
  virtual void render() {}
}

class Derived1 {
  void render() override {/*do stuff*/}
}

class Derived2 {
  void render() override {/*do stuff*/}
}

class Game {
  std::vector<Base> baseVec;

  void render() {
    for(Base b: baseVec) {
      b.render();
      //std::cout << typeid(b).name() << std::endl; prints base class' name, and requires some logic to unmangle the actual name
      //std::cout << std::type_index(typeid(b)).name() << std::endl; also prints base class' name
      //std::cout << typeNames[std::type_index(typeid(b))] << std::endl; typeNames is an unordered_map<std::type_index, std::string> - still prints the base class' name, and the list has to be punched in by hand (bad)
    }
  }
}

Upvotes: 2

Views: 679

Answers (1)

Build Succeeded
Build Succeeded

Reputation: 1150

Below code is modified for your requirement as per my understanding for your requirements:

class Base {
public:
    virtual void render() = 0;
};

class Derived1: public Base  {
    void render() override { std::cout << "Derived1"<<std::endl; }
};

class Derived2: public Base {
    void render() override { std::cout << "Derived2" << std::endl; }
};

int main()
{
    std::vector<Base*> baseVec;
    Derived1 d;
    Derived2 d1;
    baseVec.push_back(&d);
    baseVec.push_back(&d1);

        for (auto& b : baseVec)
        {
            b->render();
            std::cout << typeid(*b).name() << std::endl; 
        }

    return 0;
}

Output:

Derived1
class Derived1
Derived2
class Derived2

The typeid is solving your name by using=> typeid(*b).name().

typeid explained

Upvotes: 1

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