Assignment 5
------------

a) compile-time error, I has a pure virtual method and
   can therefore not be instantiated.

b) okay.
c) okay.
d) okay.
e) okay.
f) okay.

g) compile-time error, variable l has type I*, value e has type E*,
   but E is not a subclass of I.

h) okay.

i) compile-time error, variable g has type D*, value c has type C*,
   but C is not a subclass of D (it is the other way round).

j) okay (h receives the null pointer).

k) okay (m receives a pointer to the D object stored in d and f).

l) okay.
m) okay.
n) okay.

o) compile-time error, same justification as in g.

Assignment 4
------------

template <typename T, bool isend(T)>
int read(List<T>& list)
{
  int number = 0;
  while (true)
  {
    T elem; cin >> elem;
    if (!cin || isend(elem)) return number;
    list.add(elem);
    number++;
  }
}

template<typename T> class List
{
  Node<T> *head;
  Node<T> *tail;
  int len;
  ...
public:´
  List(): head(nullptr), tail(nullptr), len(0) { ... }
  ...
  void add(T& elem)
  {
    Node<T>* node = new Node<T>(elem, nullptr);
    if (tail == nullptr)
      head = node;
    else
      tail->next = node;
    tail = node;
    len++;
  }
}

Assignment 3
------------

template<class T>
class ArrayQueue: public BoundedQueue<T>
{
  T* array;
  int length;
  int number;
  int head; // position of front element (where to "get")
  int tail; // position after the tail element (where to "put")

public:

  ArrayQueue(int len)
  {
    array = new T[len];
    length = len;
    number = 0;
    head = 0;
    tail = 0;
  }

  ~ArrayQueue() { delete[] array; }

  bool isempty() { return number == 0; }
  bool isfull()  { return number == length; }

  void put(T& x)
  {
    array[tail] = x;
    tail = (tail+1)%length; // tail++; if (tail == length) tail = 0;
    number++;
  }

  T get()
  {
    T elem = array[head];
    head = (head+1)%length; // ...
    number--;
    return elem;
  }
};

Assignment 2
------------

void addSales(Shop& shop, Sale& sale, set<string>& names, int &turnover)
{
  map<string,Article*> articles = shop.articles();
  list<string> ids = sale.articleIds();
  for (list<string>::iterator it = ids.begin(); it != ids.end(); it++)
  {
    string id = *it;
    Article* article = articles.find(id);
    string name = article->getName();
    int price = article->getPrice();
    names.insert(name);
    turnover += price;
  }
}

set<string> getSales(Shop& shop, set<int>& days, int& turnover)
{
  set<string> names;
  turnover = 0;
  list<Sale*> sales = shop.sales();
  for (list<Sale*>::iterator it = sales.begin(); it != sales.end(); it++)
  {
    Sale* sale = *it;
    int day = sale->getDay();
    if (days.count(day) == 0) continue;
    addSale(shop, *sale, names, turnover);
  }
  return names;
}

Assignment 1
------------

class Work
{
  int cents;
  int min;

public:

  Work(int c, int m = 0): cents(c), min(m) { }
  // Work(Work& w): cents(w.cents), min(c.min) { }

  void add(int m) { min += m; }

  void printSalary()
  {
    int total = cents*min;
    cout << (total/100) << ",";
    int c = total%100;
    if (c < 10) << "0";
    cout << c;
  }

  bool subtract(int m)
  {
    if (min < m) return false;
    min -= m;
    return true;
  }

  static void reset(Work &w) { w.min = 0; }
  void reset() { /*this->*/ min = 0; }

  int compare(Work &w)
  {
    int t1 = cents*min;
    int t2 = w.cents*w.min;
    if (t1 == t2) return 0;
    if (t1 < t2) return -1;
    return 1;
  }

};