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Snippet - Simple Linked List

Simple Linked List (C++)


Created 2016-03-15 14:13:04.039690 by Matt.

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#include <iostream>

template<class T>
class LinkedListNode
{
protected:
    T data;
    LinkedListNode* next;
public:
    LinkedListNode()
        : LinkedListNode(T()) {
    }
    LinkedListNode(T value)
        : data(value), next(nullptr) {
    }
    ~LinkedListNode() {
        delete next;
    }

    void insertNode(T newValue) {
        if (!next) {
            next = new LinkedListNode(newValue);
            return;
        }

        next->insertNode(newValue);
    }

    void displayList() const {
        std::cout << data << std::endl;
        if (next) {
            next->displayList();
        }
    }

    bool deleteNode(T toBeDeleted) {
        if (!next) {
            return false;
        }

        if (next->data == toBeDeleted) {
            LinkedListNode* wasNext = next->next;

            next->next = nullptr;
            delete next;

            this->next = wasNext;

            return true;
        }

        return next->deleteNode(toBeDeleted);
    }

    T& at(int N) {
        if (N == 0) {
            return this->data;
        }

        if (!next) {
            throw "Out of bounds.";
        }

        return next->at(N-1);
    }

    int size() {
        if (!next) {
            return 1;
        }

        return 1+next->size();
    }
};

template <class T>
class LinkedList : public LinkedListNode<T>
{
public:
    LinkedList() {
    }
    ~LinkedList() {
    }

    void displayList() const {
        if (this->next) {
            this->next->displayList();
        }
    }

    T& at(int N) {
        if (!this->next) {
            throw "List is empty.";
        }
        return this->next->at(N);
    }

    int size() {
        if (!this->next) {
            return 0;
        }
        return this->next->size();
    }
};


int main(int argc, char const *argv[])
{
    LinkedList<int>* test = new LinkedList<int>();

    for (int i = 0; i < 10; ++i) {
        test->insertNode(i);
    }

    std::cout << "List of length: " << test->size() << std::endl;
    test->displayList();

    test->deleteNode(5);
    std::cout << "---- Delete Element = 5 ----" << std::endl;
    std::cout << "List of length: " << test->size() << std::endl;
    test->displayList();

    return 0;
}