C++怎么实现一个迭代器设计模式_C++ STL核心思想与自定义容器迭代器

template<typename T>
class MyVector {
private:
    T* data_;
    size_t size_;
    size_t capacity_;

public:
    class iterator {
    public:
        using value_type = T;
        using pointer = T*;
        using reference = T&;
        using difference_type = ptrdiff_t;
        using iterator_category = std::random_access_iterator_tag;
<pre class="brush:php;toolbar:false;"><pre class="brush:php;toolbar:false;">    iterator(T* ptr) : ptr_(ptr) {}

    reference operator*() const { return *ptr_; }
    pointer operator->() const { return ptr_; }

    iterator& operator++() {
        ++ptr_;
        return *this;
    }

    iterator operator++(int) {
        iterator tmp = *this;
        ++(*this);
        return tmp;
    }

    bool operator==(const iterator& other) const {
        return ptr_ == other.ptr_;
    }

    bool operator!=(const iterator& other) const {
        return !(*this == other);
    }

private:
    T* ptr_;
};

    iterator begin() { return iterator(data_); }
    iterator end() { return iterator(data_ + size_); }

MyVector<int> vec = {1, 2, 3};
for (auto& x : vec) {
    std::cout << x << " ";
}

iterator operator+(difference_type n) const {
    return iterator(ptr_ + n);
}
<p>difference<em>type operator-(const iterator& other) const {
return ptr</em> - other.ptr_;
}</p><p>bool operator<(const iterator& other) const {
return ptr<em> < other.ptr</em>;
}

class const_iterator { ... }; // 类似 iterator，但解引用返回 const T&

const_iterator begin() const { return const_iterator(data_); }
const_iterator end() const { return const_iterator(data_ + size_); }