#include <iostream>
#include <iomanip>
#include <fstream>
using namespace std;

// =============================================================================

class PlayTime {
public:
    PlayTime(int m = 0, int s = 0);
    void add(const PlayTime& t);
private:
    void normalize();
    int min;
    int sec;
friend ostream& operator<<(ostream& out, const PlayTime& t);
};

istream& operator>>(istream& in, PlayTime& t);

PlayTime::PlayTime(int m, int s): min(m), sec(s) {
    normalize();
}

void PlayTime::add(const PlayTime& t) {
    min += t.min;
    sec += t.sec;
    normalize();
}

void PlayTime::normalize() {
    long long tsec = min * 60 + sec;
    min = tsec / 60;
    sec = tsec % 60;
}

ostream& operator<<(ostream& out, const PlayTime& t) {
    return out << setfill('0') << setw(2) << t.min << ":" << setw(2) << t.sec;
}

istream& operator>>(istream& in, PlayTime& t) {
    int i;
    if (in >> i) {
        if (in.peek() == ':') {
            in.get();
            int j;
            if (in >> j) {
                t = PlayTime(i, j);
            }
        }
        else {
            t = PlayTime(0, i);
        }
    }
    return in;
}

// =============================================================================

// De class PlayList bevat:
//	-	een pointer naar een PlayListElement genaamd first dit is het eerste
//		element in de gelinkte lijst.
//		-	een PlayListElement bevat:
//			-	een PlayTime object genaamd pt.
//			-	een pointer naar een PlayListElement genaamd next.
//				(deze pointer is 0 als de lijst geen elementen meer heeft).

class PlayList {
public:
    PlayList();
    ~PlayList();
    void insert(const PlayTime& t);
    PlayTime total() const;
private:
    class PlayListElement {
    public:
        PlayTime pt;
        PlayListElement* next;
    };
    PlayListElement* first;
friend ostream& operator<<(ostream& out, const PlayList& l);
};

istream& operator>>(istream& in, PlayList& l);

PlayList::PlayList(): first(0) {
}

PlayList::~PlayList() {
    while (first != 0) {
        PlayListElement* listElement = first;
        first = first->next;
        delete listElement;
    }
}

PlayTime PlayList::total() const {
    PlayTime t;
    PlayListElement* pList = first;
    while (pList) {
        t.add(pList->pt);
        pList = pList->next;
    }
    return t;
}

void PlayList::insert(const PlayTime& t) {
    PlayListElement* newlistElement = new PlayListElement;
    newlistElement->pt = t;
    newlistElement->next = first;
    first = newlistElement;
}

ostream& operator<<(ostream& out, const PlayList& l) {
    PlayList::PlayListElement* pList = l.first;
    while (pList != 0) {
        out << pList->pt << endl;
        pList = pList->next;
    }
    return out;
}

istream& operator>>(istream& in, PlayList& l) {
    PlayTime pt;
    while (in >> pt) {
        l.insert(pt);
    }
    return in;
}

// =============================================================================

int main () {
    ifstream fin("playlist.txt");
    if (fin) {
        PlayList lijst;
        fin >> lijst;
        cout << "De lijst:" << endl << lijst;
        cout << "Totale speelduur: " << lijst.total() << endl;
    }
    else {
        cout << "De file playlist.txt kan niet worden geopend!" << endl;
    }
    cout << "Druk op de return-toets." << endl;
    cin.get();
    return 0;
}