C++ Copy Constructor and Assignment Operator

Question

I am creating a stack with the following Attributes and I am trying to create a copy-constructor and an assignment-operator but I can't since the new object and the old one point to the same memory. Please assist.

class Node
{
public:
    Node(const T& data, Node* n = 0)
    {
        element = data;
        next = n;
    }

    T element;
    Node* next;
};

/* The top of the stack */
Node* top;

Check "[What is the copy-and-swap idiom?](http://stackoverflow.com/questions/3279543/what-is-the-copy-and-swap-idiom)" — Ivan Aksamentov - Drop, Feb 16 '14 at 20:34

score 0 · Answer 1 · answered Feb 16 '14 at 20:21

0

For copy constructor do it like

Node(const Node& data)
{
    element = data.element;
    next=new Node();
    *next = *data.next;
}

answered Feb 16 '14 at 20:21

Hamza

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non-exception safe: blows up if `new` or `Node()` throws – Ivan Aksamentov - Drop Feb 16 '14 at 20:40
Thanks man, my problem was in main.cpp, I was suppose to to say Stack* newStack = new Stack(*oldStack); – Thabang Feb 19 '14 at 14:58
Np. but copy constructor is like this – Hamza Feb 19 '14 at 17:03

score 0 · Answer 2 · answered Jan 09 '19 at 01:12

Assignment Operator :

Node& operator=(const Node& data) {
    if (this != &other) { // to avoid self-assignment
        element = data.element;

        // allocate new memory
        Node* tmp = new Node();
        std::memcpy(tmp, data.next, sizeof(Node));

        // deallocate old memory
        delete next;

        // assign new memory to object
        next = new Node();
        std::memcpy(next, tmp, sizeof(Node));
    }
    return *this; 
}

Exception safety is taken into consideration.

C++ Copy Constructor and Assignment Operator

2 Answers2