Modifying member functions of built-in objects

Question

I'm sure this has been answered many times, but I don't know how to search for this. Is this polymorphism? Overloading?

Basically I want to take a vector, and modify its functions the way I want them or create new ones.

E.g: I want push_back() to insert an element and keep the vector in descending order. So the addition would be to swap() the element to its respective place. Or I would like to add a new function pop_front().

That being said, I need it as a member function, e.g:

vector<int> x;
x.pop_front();

not:

pop_front(x);

Is this ever done in practice? I know I can just use existing containers, like a priority queue for my example, but I'd rather make completely custom functions.

http://stackoverflow.com/questions/6806173/subclass-inherit-standard-containers might be helpful to you. — James Picone, Dec 03 '15 at 02:08
C++17 is hopefully going to make `x.foo()` and `foo(x)` equivalent — M.M, Dec 03 '15 at 02:36

score 1 · Accepted Answer · answered Dec 03 '15 at 02:11

Basically, std::vector is not designed to be base class, inherit from it would be a bad idea in general. For example its dtor is not virtual.

It's better to use composition here. e.g.

template <typename T>
class MyVector {
private:
    std::vector<T> v;
public:
    void pop_front() {
        // processing on v ...
    }
};

Modifying member functions of built-in objects

1 Answers1