CODEWITHSUNDEEP
c++inheritancepolymorphismderived
Lukesmith
Lukesmith

Reputation: 170

Store derived object in vector of base type

I have a std::vector of pointers of a base class type:

vector<Base*> baseList;

And I push a derived class type onto the vector:

Derived* derivedObject = new Derived();
baseList.push_back(derivedObject);

But when I iterate the list and call the function which is overridden from the base class by the derived class the code in the derived class isn't called. Am I using the vector in the correct way?

My base class has uses the virtual keyword before declaring its functions and the derived class derives the base class with:

class Derived : public Base

Any Idea what I'm doing wrong here?

EDIT:

To call the function I have declared:

typedef vector<App*>::iterator AppIterator;
AppIterator begin() { return l_Apps.begin(); }
AppIterator end()   { return l_Apps.end(); }

And I call the function like so:

for (AppIterator it = begin(); it != end(); ++it)
{
    (*it)->Initialize();
}

Could the problem be here?

Upvotes: 0

Views: 2981

Answers (1)

Kupto
Kupto

Reputation: 2992

I tried the thing with iterator... this code works fine for me, so if your problem persists, consider different compiler =)

#include <iostream>
#include <vector>

class Base
{
public:
    virtual void f()
    {
        std::cout << "Base\n";
    }
};
class Derived: public Base
{
public:
    virtual void f()
    {
        std::cout << "Derived\n";
    }
};
int main()
{
    std::vector<Base*> s;
    s.push_back(new Base());
    s.push_back(new Derived());
    s.push_back(new Base());
    s.push_back(new Derived());
    s.push_back(new Base());
    s.push_back(new Derived());
    for (std::vector<Base*>::iterator it = s.begin(); it != s.end(); ++it)
    {
        (*it)->f();
    }
    return 0;
}

the output I have:

Base
Derived
Base
Derived
Base
Derived

also you might try to cast the pointers by dynamic_cast<>, even though it defeats the whole point of using virtual methods. Good luck.

Upvotes: 1

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