Deque リストを作成する必要があり、Deque リスト内には、リスト内の値を見つけるための関数呼び出し find があります。しかし、そのノードに探している値が含まれていない場合、反復を次のノードに移動しようとすると問題が発生します。彼女は私の検索機能のスニペットです:
unique_ptr<DequeIterator<E>> find(E match)
{
assert(!is_empty());
bool is_found = true;
// set the pointer point to the first node from the beginning
unique_ptr<DequeIterator<E>> iter(iter_begin());
while(iter->node()->value() != match)
{
// here is I want to move the iter position
// over to the next node
iter->next();
// print out the value at the node to re-check if
// it matches
cout << iter->node()->value() << endl;
}
if(is_found)
{
cout << "found" << iter->node()->value() << endl;
}
else
cout << "no match" << endl;
return iter;
}
unique_ptr<DequeIterator<E>> iter_begin()
{
// _head is set to nullptr inside the constructor
return unique_ptr<DequeIterator<E>>(new DequeIterator<E>(_head));
}
DequeIterator クラス
template<class E>
class DequeIterator {
public:
// You may need to modify this class. Feel free to modify the definitions of
// these functions, or add new member functions.
DequeIterator(DNode<E>* node) {
_node = node;
}
bool at_end() {
return _node == nullptr;
}
E value() {
assert(!at_end());
return _node->value();
}
void set_value(E x) {
assert(!at_end());
_node->set_value(x);
}
void next() {
assert(!at_end());
_node = _node->next();
}
DNode<E>* node() { return _node; }
private:
DNode<E>* _node;
};
これは私の DNode クラスです
template<class E>
class DNode {
public:
DNode(DNode<E>* prev, E value, DNode<E>* next) {
_value = value;
_prev = prev;
_next = next;
dnode_census++;
}
~DNode() {
dnode_census--;
}
// The program crashes right here
// after it goes into the E value()
E value() { return _value; }
void set_value(E value) { _value = value; }
DNode<E>* prev() { return _prev; }
void set_prev(DNode<E>* prev) { _prev = prev; }
DNode<E>* next() { return _next; }
void set_next(DNode<E>* next) { _next = next; }
private:
E _value;
DNode<E> *_prev;
DNode<E> *_next;
};
デキュークラス
template<class E>
class Deque {
public:
Deque()
{
_head = 0;
_size = 0;
_tail = 0;
}
~Deque() {
clear();
}
// Make the deque empty. O(n) time.
void clear() {
while (!is_empty())
erase_back();
}
// Return the current size of the deque. O(1) time.
int size() {
return _size;
}
// Return true when the deque is empty. O(1) time.
bool is_empty() {
return (size() == 0);
}
unique_ptr<DequeIterator<E>> iter_begin()
{
return unique_ptr<DequeIterator<E>>(new DequeIterator<E>(_head));
}
unique_ptr<DequeIterator<E>> iter_at(int index)
{
assert((index >= 0) && (index <= size()));
unique_ptr<DequeIterator<E>> iter(iter_begin());
for(int j = 0; j < index; j++)
iter->next();
return iter;
}
E front()
{
assert(!is_empty());
return _head->value();
}
E back()
{
assert(!is_empty());
return _tail->value();
}
void insert_after(DequeIterator<E>& iter, E x)
{
if(_size == 0)
{
insert_front(x);
}
else
{
assert(!iter.at_end());
DNode<E>* temp = new DNode<E>(iter.node(), x, iter.node()->next());
iter.node()->next()->set_next(temp);
iter.node()->next()->set_prev(temp);
}
_size++;
}
void insert_before(DequeIterator<E>& iter, E x)
{
if(_size == 0)
{
insert_front(x);
}
else
{
assert(!is_empty());
DNode<E>* temp2 = new DNode<E>(iter.node()->prev(), x, iter.node());
(iter.node()->prev())->set_next(temp2);
(iter.node()->prev())->set_prev(temp2);
}
_size++;
}
void insert_front(E x)
{
if(is_empty())
{
DNode<E>* temp = new DNode<E>(nullptr, x, nullptr);
_head = temp;
_tail = temp;
}
else
{
DNode<E>* temp = _head;
DNode<E>* temp2 = new DNode<E>(nullptr, x, temp);
_head = temp2;
}
_size++;
}
void insert_back(E x)
{
if(is_empty())
{
insert_front(x);
}
else
{
assert(!is_empty());
DNode<E>* temp = new DNode<E>(_tail, x, nullptr);
_tail = temp;
_size++;
if(_size > 1)
cout << _tail->prev()->value() << endl;
}
}
void erase(DequeIterator<E>& iter)
{
assert((!is_empty()) || !iter.at_end());
DNode<E>* temp = iter.node();
temp->next()->set_prev(temp->prev());
temp->prev()->set_next(temp->next());
delete iter.node()->next();
_size--;
}
void erase_front()
{
assert(!is_empty());
DNode<E>* temp = _head;
_head = temp->next();
delete temp;
_size--;
}
void erase_back()
{
assert(!is_empty());
DNode<E>* temp = _tail;
_tail = temp->prev();
delete temp;
_size--;
}
unique_ptr<DequeIterator<E>> find(E match)
{
assert(!is_empty());
bool is_found = true;
unique_ptr<DequeIterator<E>> iter(iter_begin());
while(iter->value() != match)
{
iter->next();
cout << iter->value() << endl;
}
if(is_found)
{
cout << "found" << iter->node()->value() << endl;
}
else
cout << "no match" << endl;
return iter;
}
// Return the element value at position index, which must be
// valid. O(n) time.
E get(int index)
{
assert((index >= 0) && (index < size()));
unique_ptr<DequeIterator<E>> iter(iter_begin());
for(int j = 0; j < index; j++)
iter->next();
return iter->node()->value();
}
void meld(Deque<E>& other)
{
}
private:
DNode<E>* _head;
DNode<E>* _tail;
int _size;
};
main.cpp
int main() {
assert_no_leak(0);
// Element objects to reuse. All upper case letters of the alphabet.
//const int N = 5;
const int N = 26;
char letters[N];
for (int i = 0; i < N; i++)
letters[i] = 'A' + i;
// Now there are a series of unit tests. Each test checks a few
// related member functions. The tests use assert(...) to look for
// bugs, so if one of these assertions fails, that indicates a bug
// in your deque code.
print_test_title("Deque constructor");
unique_ptr<Deque<char>> q(new Deque<char>());
assert_no_leak(0);
print_test_title("Deque::size");
assert(q->size() == 0);
print_test_title("Deque::is_empty");
assert(q->is_empty());
print_test_title("Deque::insert_back");
for (int i = 0; i < N; i++) {
assert(q->size() == i);
assert_no_leak(i);
q->insert_back(letters[i]);
assert(!q->is_empty());
assert(q->size() == (i+1));
assert_no_leak(i+1);
}
print_test_title("iteration");
unique_ptr<DequeIterator<char>> iter(q->iter_begin());
assert(!iter->at_end());
assert_no_leak(N);
for (int i = 0; !iter->at_end(); i++, iter->next()) {
assert(i < N);
assert(iter->value() == letters[i]);
assert_no_leak(N);
}
assert_no_leak(N);
/* for (int i = 0; i < N; i++)
cout << q->get(i) << endl;*/
print_test_title("Deque::find");
iter = q->find('A');
assert(!iter->at_end());
assert(iter->value() == 'A');
assert_no_leak(N);
**// This is where I got the unhandled exception**
iter = q->find('T');
assert(!iter->at_end());
assert(iter->value() == 'T');
assert_no_leak(N);
iter = q->find('?');
assert(iter->at_end());
assert_no_leak(N);
print_test_title("Deque::get");
for (int index = 0; index < N; index++) {
assert(q->get(index) == letters[index]);
assert_no_leak(N);
}
print_test_title("Deque::front");
assert(q->front() == 'C');
assert_no_leak(N);
print_test_title("Deque::back");
assert(q->back() == 'Z');
assert_no_leak(N);
print_test_title("Deque::erase_front");
for (int i = 0; i < N; i++) {
assert(q->front() == letters[i]);
assert(q->size() == (N-i));
assert_no_leak(N-i);
q->erase_front();
}
assert(q->is_empty());
assert_no_leak(0);
print_test_title("Deque::erase_back");
for (int i = 0; i < N; i++)
q->insert_back(letters[i]);
for (int i = 0; i < N; i++) {
assert(q->back() == letters[N-i-1]);
assert(q->size() == (N-i));
assert_no_leak(N-i);
q->erase_back();
}
assert(q->is_empty());
assert_no_leak(0);
print_test_title("Deque::insert_front");
for (int i = 0; i < N; i++) {
q->insert_front(letters[i]);
assert(q->front() == letters[i]);
assert(q->size() == (i+1));
assert_no_leak(i+1);
}
assert(q->size() == N);
assert_no_leak(N);
print_test_title("Deque::clear");
q->clear();
assert(q->is_empty());
assert_no_leak(0);
for (int size = 0; size <= N; size++) {
assert(q->is_empty());
assert_no_leak(0);
for (int i = 0; i < size; i++)
q->insert_back(letters[i]);
assert(q->size() == size);
assert_no_leak(size);
q->clear();
assert(q->is_empty());
assert_no_leak(0);
}
print_test_title("insert_after, insert_before, erase");
assert(q->is_empty());
iter = q->iter_begin(); // iter is at end of empty queue
q->insert_before(*iter, 'X');
assert(queue_equals_string(*q, "X"));
assert_no_leak(1);
iter = q->iter_begin(); // iter is at start of queue with 1 element
q->insert_after(*iter, 'O');
assert(queue_equals_string(*q, "XO"));
assert_no_leak(2);
q->insert_after(*iter, 'Z');
assert(queue_equals_string(*q, "XZO"));
assert_no_leak(3);
iter->next(); // iter is at second position (Z)
q->insert_before(*iter, 'C');
assert(queue_equals_string(*q, "XCZO"));
assert_no_leak(4);
q->insert_after(*iter, 'A');
assert(queue_equals_string(*q, "XCZAO"));
assert_no_leak(5);
iter->next(); // iter is at fourth position (A)
q->erase(*iter); // erase A
assert(queue_equals_string(*q, "XCZO"));
assert_no_leak(4);
iter = q->iter_begin(); // X
iter->next(); // C
iter->next(); // Z
q->erase(*iter); // erase Z
assert(queue_equals_string(*q, "XCO"));
assert_no_leak(3);
q->erase(*q->iter_begin()); // erase X
assert(queue_equals_string(*q, "CO"));
assert_no_leak(2);
iter = q->iter_begin(); // erase O
iter->next();
q->erase(*iter);
assert(queue_equals_string(*q, "C"));
assert_no_leak(1);
q->erase(*q->iter_begin()); // erase C
assert(queue_equals_string(*q, ""));
assert_no_leak(0);
print_test_title("Deque::splice");
assert(q->is_empty());
assert_no_leak(0);
unique_ptr<Deque<char>> q2(new Deque<char>());
assert_no_leak(0);
for (int i = 0; i < 5; i++) {
q->insert_back(letters[i]);
q2->insert_back(letters[i]);
}
assert(q->size() == 5);
assert(q2->size() == 5);
assert_no_leak(10);
q->meld(*q2);
assert(q->size() == 10);
assert(q2->is_empty());
assert_no_leak(10);
assert(queue_equals_string(*q, "ABCDEABCDE"));
if (DO_PERFORMANCE_TEST) {
print_test_title("Performance");
q->clear();
time_t start = time(nullptr);
for (int i = 0; i < BIG_N; i++) {
q->insert_front('A');
if ((i % 1000) == 0)
cout << '.';
}
time_t stop = time(nullptr);
assert(q->size() == BIG_N);
cout << endl
<< " Elapsed time to insert_front " << BIG_N << " times: "
<< (stop - start) << " seconds" << endl;
}
return 0;
}