如何创建深拷贝构造函数？

Question

I have this code, and I have to create a copy constructor for it to create a deep copy of the passed object. How can I create that?

template<typename T>
class SSL {
    struct Node {
        T data;
        Node* next;
    };
    Node* head = nullptr;
public:
    // ...
};

Answer 1

You simply need to iterate the source object's list, making new nodes that have copies of its data, eg:

template <typename T>
class SSL {
    struct Node {
        T data;
        Node* next = nullptr;
        Node(const T &value) : data(value) {}
    };

    Node* head = nullptr;

public:
    // ...

    SSL() = default;

    SSL(const SSL &src) {
        Node **n = &head;
        for (Node *cur = src.head; cur; cur = cur->next) {
            *n = new Node{cur->data};
            n = &(n->next);
        }
    }

    SSL(SSL &&src) : head(src.head) {
        src.head = nullptr;
    };

    ~SSL() {
        Node *cur = head;
        while (cur) {
            Node *n = cur;
            cur = cur->next;
            delete n;
        }
    }

    SSL& operator=(SSL rhs) {
        std::swap(head, rhs.head);
        return *this;
    }

    // ...
};