int main() {
// Demo the use of our LinkedList class.
LinkedList<int> l; // TData is int....
l.AddFirst(1); // ... so all the Add methods take ints.
l.AddFirst(2);
l.AddFirst(3);
l.AddLast(4);
l.AddLast(5);
// Use the .Get method to access individual elements.
// How efficient is this loop? Not as efficient.
// The loop takes too long to walk through all elements of linked lists
// if the size of linked list is large.
for (int i = 0; i < l.Size(); i++) {
cout << l.Get(i) << endl;
}
cout << "Remove: " << endl;
// The .RemoveFirst/Last/At methods return the data removed.
while (l.Size() > 0) {
cout << l.RemoveFirst() << endl;
}
cout << endl;
// It is easy to get the "border" cases wrong in a linked structure. Let's
// test to see what happens when adding to a list that had just been emptied.
l.AddFirst(1);
l.AddFirst(2);
l.AddFirst(3);
l.AddLast(4);
l.AddLast(5);
cout << "After adding back to the emptied list:" << endl;
for (int i = 0; i < l.Size(); i++) {
cout << l.Get(i) << endl;
}
// Does that look correct?
cout << endl;
cout << "Contains 14? " << endl;
// Demo the Contains method. Will this be true or false?
cout << l.Contains(14) << endl;
cout << endl;
// So far we have used the LinkedList directly, so the List base class
// doesn't seem necessary. Through polymorphism, we can declare a List
// pointer to a LinkedList object.
List<int> *p = new LinkedList<int>();
// We can now only call List<int> methods on p... which, fortunately, is all
// of our important functions.
p->AddLast(4);
p->AddLast(8);
p->AddLast(15);
p->AddLast(16);
p->AddLast(23);
p->AddLast(42);
cout << "Pointer to a List contains 16? " << p->Contains(16) << endl;
// So far we don't have much of a reason to do this type of polymorphism.
// But we will...
// Lecture part 2: iterators!
// Picture the normal iterator loop:
// for (_____::iterator itr = _____.begin(); itr != _____.end(); itr++) {
// do something with *itr or itr->
/*
If we want our LinkedList to follow this trend, what do we need to
implement?
1. An inner class named iterator, so our full scoped name will be
LinkedList<TData>::iterator
2. Operators ++, ==, !=, *, and -> in the iterator class.
3. Member methods .begin() and .end() in LinkedList.
When those are implemented, we can then...
*/
cout << endl << "ITERATORS!!!" << endl;
for (LinkedList<int>::iterator itr = l.begin(); itr != l.end(); itr++) {
cout << *itr << endl;
}
}
