我已经运行了很多次。我尝试修复我的deleteNode()和addNode(),但没有成功。输出显示我无法在列表中添加一些有效条目,从而导致无法删除这些有效条目。有人请帮助我找到错误...我认为我的isEmpty()错误或addNode搞砸了。
// Add nodes and makes it work in any cases: backward/forward
bool LinkedList::addNode(int id, string str) {
bool result = false;
if (id >= 0 && !(idExists(id))) {
Node *current = head;
Node *temp = new Node;
temp->data.data = str;
temp->data.id = id;
temp->forward = NULL;
temp->back = NULL;
// Kinds of adding cases
if(head == NULL) { // Check if list is empty
addHead(temp, current);
result = true;
} else {
while(temp->data.id > current->data.id && current->forward != NULL) {
current = current->forward;
}
// Backward
if(current->back == NULL) {
if(temp->data.id > current->data.id) {
if(current->forward == NULL) {
addTail(temp, current);
} else {
addMiddle(temp, current);
}
} else {
addHead(temp, current);
}
result = true;
// Forward
}else if(current->forward == NULL) {
if (temp->data.id > current->data.id) {
addTail(temp, current);
} else {
addMiddle(temp, current);
}
result = true;
}else {
if(temp->data.id > current->data.id) {
addMiddle(temp, current);
result = true;
}
}
}
}
return result;
}
void LinkedList::addHead(Node *temp, Node *current) {
if (head != NULL){
temp->forward = current;
current->back = temp;
head = temp;
} else {
head = temp;
}
}
void LinkedList::addMiddle(Node *temp, Node *current) {
temp->forward = current;
temp->back = current->back;
current->back->forward = temp;
current->back = temp;
}
void LinkedList::addTail(Node *temp, Node *current) {
current->forward = temp;
temp->back = current;
}
// Delete list
bool LinkedList::deleteNode(int id){
bool result = false;
if (idExists(id)) {
Node *current = head;
while (current->forward != NULL && current->data.id != id) {
current = current->forward;
}
if (current->data.id == id && current->forward == NULL) {
if (current->back == NULL) { // Delete head
delete current;
head = NULL;
} else { // delete tail
deleteTail(current);
}
result = true;
} else if (current->data.id == id) {
if (current->back == NULL)
deleteHead(current);
else // delete middle
deleteMiddle(current);
result = true;
}
}
return result;
}
// Helper delete functions
void LinkedList::deleteHead(Node *current) {
head = current->forward;
head->back = NULL;
delete current;
}
void LinkedList::deleteMiddle(Node *current) {
current->back->forward = current->forward;
current->forward->back = current->back;
delete current;
}
void LinkedList::deleteTail(Node *current) {
current->back->forward = NULL;
delete current;
}
bool LinkedList::getNode(int id, Data *data) {
bool didGetNode = false;
if (idExists(id)) {
Node *current = head;
while (current->forward != NULL && current->data.id != id) {
current = current->forward;
}
data->id = current->data.id;
data->data = current->data.data;
didGetNode = true;
}
return didGetNode;
}
// Check whether or not the id exists
bool LinkedList::idExists(int id){
bool exists = false;
if (head != NULL){
Node *current = head;
while (current->forward != NULL && current->data.id != id) {
current = current->forward;
}
if (current->data.id == id) {
exists = true;
}
}
return exists;
}
好像您想在addTail和其他函数中传递指向指针(**)的指针或指向引用(*&)的指针。