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#include "linkedlist.h"
LinkedList::LinkedList() : Collection(), head(NULL), tail(NULL)
{
}
LinkedList::LinkedList(const LinkedList& list) : Collection(list), head(NULL), tail(NULL)
{
Node *iter = list.tail;
while (iter) {
this->add(iter->v);
iter = iter->prev;
}
}
LinkedList& LinkedList::operator=(const Collection& rhs)
{
if (this == &rhs)
return *this;
this->cleanup();
this->size_ = 0;
Node *iter = dynamic_cast<const LinkedList *>(&rhs)->head; /* it's ok g++ */
while (iter) {
this->add(iter->v);
iter = iter->next;
}
return *this;
}
LinkedList::~LinkedList()
{
this->cleanup();
}
void LinkedList::cleanup(void)
{
Node *iter, *prev;
iter = prev = this->head;
while (iter) {
prev = iter;
iter = iter->next;
delete prev;
}
}
void LinkedList::add(int n)
{
Node *node = new Node();
node->v = n;
node->next = this->head; /* link next */
if (!this->head) /* first node */
this->tail = node; /* this where tail gets assigned */
else
this->head->prev = node; /* link prev */
this->head = node;
this->size_++;
}
bool LinkedList::remove(int n)
{
if (!this->head)
return false;
if (this->head->v == n) { /* deleting first element or head */
Node *first = this->head;
this->head = this->head->next;
if (this->get_size() == 1)
this->tail = NULL; /* tail gets nuked here */
delete first;
return true;
}
else if (this->tail->v == n) { /* deleting last element or tail */
Node *last = this->tail;
this->tail = this->tail->prev;
this->tail->next = NULL;
delete last;
return true;
}
Node *iter = this->head;
while (iter) {
if (iter->v == n) {
iter->prev->next = iter->next;
delete iter;
this->size_--;
return true;
}
iter = iter->next;
}
return false;
}
/* assumes first element is at index of zero */
int LinkedList::operator[](int i)
{
/* invalid accesses */
if (!this->size_ || i < 0 || i+1 > this->size_)
return -1;
Node *iter = this->head;
int cnt = this->size_ - i - 1;
while (cnt--) {
iter = iter->next;
}
return iter->v;
}
LinkedList *LinkedList::copy(void)
{
LinkedList *ret = new LinkedList(*this);
return ret;
}
void LinkedList::iterate(void (*modifier)(int *))
{
Node *iter = this->head;
while (iter) {
modifier(&iter->v); /* missing smalltalk? No! */
iter = iter->next;
}
}
bool LinkedList::contains(int i) const
{
Node *iter;
for (iter = this->head; iter != NULL && iter->v != i; iter = iter->next)
;
return iter ? true : false;
}
void LinkedList::print_helper(std::stringstream& sstm, Node *n) const
{
if (!n)
return;
print_helper(sstm, n->next);
sstm << n->v << " ";
}
/* does a recursive print since ll is inverted with respect to array */
/* could just use tail and iterate through prev pointers */
std::string LinkedList::print() const
{
std::stringstream sstm;
print_helper(sstm, this->head);
return sstm.str();
}
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