将迭代器返回到可与此内部成员函数一起使用的私有变量

#include <iostream>
#include <vector>

class MyContainer {
private:
    std::vector<int> data;

public:
    MyContainer(std::initializer_list<int> init) : data(init) {}

    class Iterator {
    private:
        std::vector<int>::iterator it;
    public:
        Iterator(std::vector<int>::iterator iter) : it(iter) {}

        bool hasNext() const {
            return it != data.end();
        }

        int next() {
            return *it++;
        }
    };

    Iterator getIterator() {
        return Iterator(data.begin());
    }

    friend class Iterator; // 允许迭代器访问私有成员
};

int main() {
    MyContainer container = {1, 2, 3, 4, 5};
    MyContainer::Iterator it = container.getIterator();

    while (it.hasNext()) {
        std::cout << it.next() << " ";
    }
    return 0;
}