Linked List - Iter

linked list 자료구조 연습
(아직 미완)

#include <iostream>
using namespace std;

template<class T> class Chain;
template<class T> class ChainIterator;

template<class T> class ChainNode {
    friend class Chain<T>;
    friend class ChainIterator<T>;
public:
    ChainNode(T element = 0);
private:
    T data;
    ChainNode<T>* link;
};

template<class T> class Chain {
    friend class ChainIterator<T>;
public:
    Chain() {first = 0;};
    void Delete(void);
    int Length();
    void Add(const T& element);
    void Invert();
    void Concatenate(Chain<T> b);
    //template <class T>
    friend ostream& operator<<(ostream&, Chain<T>);
    //int Minimum();
private:
    ChainNode<T>* first;
};

template<class T>
class ChainIterator {
public:
    ChainIterator(const Chain<T>& I):list(I), current(I.first) {};
    T& operator *() const {return current->data;};
    T* operator ->() const {return &current->data;};
    //increment
    ChainIterator<T>& operator ++();
    ChainIterator<T> operator ++(int);
    bool NotNull();
    bool NextNotNull();

    T* First();
    T* Next();
private:
    const Chain<T>& list; //refers to an existing list
    ChainNode<T>* current; // points to a node in list
};

template<class T>
ChainNode<T>::ChainNode(T element) {
    data = element;
    link = 0;
}

template<class T>
void Chain<T>::Delete(void) {
    ChainNode<T>* current, *next;
    if(first != nullptr) {
        next = first->link;

        ChainNode<T>* temp = first;
        first = next;
        delete temp;
    }
    else cout << "Error - Empty List. Not deleted" << "\n";
}

template<class T>
void Chain<T>::Add(const T& element) {
    ChainNode<T>* newNode = new ChainNode<T>(element);

    if(!first) {
        first = newNode;
        return;
    }
    newNode->link = first;
    first = newNode;
}

template<class T>
void Chain<T>::Invert() {
    ChainNode<T>* p =first, *q = 0; //q trails p
    while(p) {
        ChainNode<T>* r = q;
        q = p;
        p = p->link;
        q->link = r;
    }
    first = q;
}

template<class T>
void Chain<T>::Concatenate(Chain<T> b) {
    ChainNode<T>* p;
    if(!first) {
        first = b.first;
        return;
    }
    if(b.first) {
        for(p = first; p->link;p = p->link)
            p->link = b.first;
    }
}

template<class T>
ChainIterator<T>& ChainIterator<T>:: operator++() {
    current = current->link;
    return *this;
}

template<class T>
ChainIterator<T> ChainIterator<T>::operator++(int) {
    ChainIterator<T> old = *this;
    current = current->link;
    return old;
}

template<class T>
bool ChainIterator<T>::NotNull() {
    if(current) return 1;
    else return 0;
}

template<class T>
bool ChainIterator<T>::NextNotNull() {
    if(current && current->link) return 1;
    else return 0;
}

template<class T>
T* ChainIterator<T>::First() {
    if(list.first) return &list.first->data;
    else return 0;
}

template<class T>
T* ChainIterator<T>::Next() {
    if(current) {
        current = current->link;
        return &current->data;
    }
    else return 0;
}

template<class T>
int Show(const Chain<T>& I) {
    ChainIterator<T> li(I);

    if(!li.NextNotNull()) return 0;

    T retvalue = *li.First();
    cout << retvalue;

    while(li.NextNotNull()) {
        retvalue = *li.Next();
        cout << " <- " << retvalue;
    }
    return retvalue;
}

template<class T>
int sum(const Chain<T>& I) {
    ChainIterator<T> li(I);

    if(!li.NotNull()) return 0;

    T retvalue = *li.First();
    while(li.NextNotNull()) {
        retvalue += *li.Next();
    }
    return retvalue;
}

template<class T>
int SumProductFifth(const Chain<T>& I) {
    // Sum(Xi * Xi+5)
    return 0;
}

template<class T>
int Length(const Chain<T>& I) {
    //list 갯수
    return 0;
}

template<class T>
int Maximum(const Chain<T>& I) {
    //list에서 최솟값
    return 0;
}

template<class T>
int Minimun(const Chain<T>& I) {
    //list에서 최솟값
    return 0;
}

template<class T>
int MakeArray(const Chain<T>& I, int []) {
    //list 원소를 읽어 배열에 저장
    return 0;
}

int main(void) {
    int select;
    //ChainNode<int> nd;
    Chain<int> a, b;
    ChainIterator<int> cit(a);
    int value;
    do{
        cout << "\n1. Add new value to chain 'A\n2. Add new value to chain 'B'";
        cout << "\n3. Print all chains\n4. Invert Chain\n5. Concatenate A and B\n6. Delete first node in Chain";
        cout << "\n7. Get Sum of the chain\n8. Get length of the chain\n9. Get Max val in Chain\n10. Quit\n";
        cout << "Selet command(1~10) : ";
        cin >> select;
        switch (select)
        {
        case 1:
            cout << "Add a new value: ";
            cin >> value;
            a.Add(value);
            break;
        case 2:
            cout << "Add a new value: ";
            cin >> value;
            b.Add(value);
            break;
        case 3:
            cout << "Chain A: ";
            Show(a);
            cout << "\n";
            cout << "Chain B: ";
            Show(b);
            cout << "\n";
        case 4:
            cout << "\nWhich chain will you invert?\n1. Chain A\n2.Chain B\n\nSelect command(1~2) : ";
            cin >> value;
            if(value == 1) {
                a.Invert();
            } else if(value == 2) {
                b.Invert();
            } else {
                cout << "Invalid value\n";
            }
            break;
        case 5:
            cout << "\nConcatenate chain\n";
            a.Concatenate(b);
            Show(a);
            cout << "\n";
            break;
        case 6:
            cout << "\nWhich chain will you delete?\n[1] Chain A\n[2]Chain B\n\nSelect Command(1~2) : ";
            cin >> value;

            if(value == 1)
                a.Delete();
            else if(value == 2)
                b.Delete();
            else
                cout << "Invalid value\n";
            break;
        case 7:
            cout << "\nWhich chain will you sum?\n[1]Chain A\n[2]Chain B\n\nSelect Command(1~2) : ";
            cin >> value;

            if(value == 1)
                sum(a);
            else if(value == 2)
                sum(b);
            else
                cout << "Invalid value\n";
            break;
        case 8:
            cout << "\nWhich chain's length do you want?\n[1]Chain A\n[2]Chain B\n\nSelect Command(1~2) : ";
            cin >> value;

            if(value == 1)
                cout << Length(a) << "\n";
            else if(value == 2)
                cout << Length(b) << "\n";
            else
                cout << "Invalid value\n";
            break;
        case 9:
        cout << "\nWhich chain's max-value do you want?\n[1]Chain A\n[2]Chain B\n\nSelect Command(1~2) : ";
            cin >> value;

            if(value == 1)
                cout << Maximum(a) << "\n";
            else if(value == 2)
                cout << Maximum(b) << "\n";
            else
                cout << "Invalid value\n";
            break;
        case 10:
            cout << "Quit the program...";
            break;
        default:
            cout << "WRONG INPUT\n"; 
            break;
        }
    } while(select != 10);
    system("pause");
    return 0;
}