CODEWITHSUNDEEP
c++inheritancevector
meernet
meernet

Reputation: 386

Abstract class, how to call function print

I have a problem, I have this base class:

class A{
public:
    /*...*/
    virtual void print() = 0;
};

And here I make one class which inherits from class "A"

class B : public A{
private:
    double a;
public:
    /*...*/
    B(double _a) : a(_a){ }
    void print() override{
        cout << a<<'\n';
    }
};

And I use:

int main(){
/*...*/ 
std::vector<A*> vec; 
/* ... Here I added new object */
vec.push_back(new B(2)); 

for(__typeof(vec.begin()) it = (vec.begin()); it!= vec.end(); it++){
}
   //How to using and display function print which is declared inside class B
}

Question: How to call function print which is declared inside class B?

I have tried using following method but this notation don't give me a good result:

vec.front()->print();

Upvotes: 0

Views: 384

Answers (2)

quamrana
quamrana

Reputation: 39404

Your main just needs to be like this:

int main(){

    std::vector<A*> vec; 
    /* ... Here I added new object */
    vec.push_back(new B(2)); 

    for(std::vector<A*>::iterator it = vec.begin(), end = vec.end(); it != end; ++it){
        (*it)->print();
    }

    return 0;
}

Note how the iterator is dereferenced inside the loop.

Upvotes: 5

Chris Drew
Chris Drew

Reputation: 15334

In your loop you need to dereference the iterator and the contained pointer. So write something like:

(*it)->print();

But you might want to consider a C++11 ranged-based for loop instead:

for (auto ptr : vec)
    ptr->print();

Upvotes: 2

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