【发布时间】：2018-04-14 14:32:11
【问题描述】：
我正在尝试使用虚拟节点（centinels）实现 Dequeue。当我尝试编译时，出现分段错误 11 错误。这是我的代码：（非常感谢！！）
节点.h：
template <class Element>
class Node {
public:
Node(const Node& orig);
Node(Element e);
const Element& getElement();
Node<Element>* getNext() const;
void setNext(Node<Element> *next);
Node<Element>* getPrevious() const;
void setPrevious(Node<Element> *prev);
~Node();
private:
Node <Element>* next;
Node <Element>* prev;
Element element;
};
template <class Element>
Node<Element>::Node(Element e){
this->element = e;
this->next = nullptr;
this->prev= nullptr;
}
template <class Element>
Node<Element>::~Node(){
}
template <class Element>
const Element& Node<Element>::getElement(){
return this->element;
}
template <class Element>
Node<Element>* Node<Element>::getNext() const{
return this->next;
}
template <class Element>
Node<Element>* Node<Element>::getPrevious() const{
return this->prev;
}
template <class Element>
void Node<Element>::setNext(Node<Element>* next){
this->next = next;
}
template <class Element>
void Node<Element>::setPrevious(Node<Element>* prev){
this->prev = prev;
}
LinkedDeque.h：
#ifndef LINKEDDEQUE_H
#define LINKEDDEQUE_H
#include "Node.h"
#include <iostream>
using namespace std;
template <class Element>
class LinkedDeque {
public:
LinkedDeque();
~LinkedDeque();
LinkedDeque(const LinkedDeque<Element>& deque);
bool isEmpty()const;
void insertFront(const Element & element);
void insertRear(const Element & element);
void deleteFront();
void deleteRear();
void print();
const Element& getFront()const;
const Element& getRear()const;
private:
int num_elements;
Node<Element> *_front;
Node<Element> *_rear;
Node<Element> *frontSentinel;
Node<Element> *rearSentinel;
};
template <class Element>
LinkedDeque<Element>::LinkedDeque(){
//creamos nodos vacios
_front->setNext(frontSentinel);
_rear->setPrevious(rearSentinel); //**************
int num_elements = 0;
cout << "Holi" << endl;
}
//cal implementar el constructor copia
template <class Element>
LinkedDeque<Element>::LinkedDeque(const LinkedDeque<Element>& deque){
}
template <class Element>
LinkedDeque<Element>::~LinkedDeque() {
}
template <class Element>
bool LinkedDeque<Element>::isEmpty()const{
return (this->frontSentinel->getNext()==nullptr);
}
template <class Element>
void LinkedDeque<Element>::insertFront(const Element & element){
Node<Element> *new_node = new Node<Element> (element);
if(isEmpty()){
rearSentinel->setPrevious(new_node);
frontSentinel->setNext(new_node);
}else{
Node<Element> *aux;
aux = frontSentinel->getNext();
frontSentinel->setNext(new_node);
aux->setPrevious(frontSentinel->getNext());
delete aux;
}
num_elements++;
}
template <class Element>
void LinkedDeque<Element>::insertRear(const Element & element){
Node<Element> *new_node = new Node<Element> (element);
if(isEmpty()){
rearSentinel->setPrevious(new_node);
frontSentinel->setNext(new_node);
}else{
Node<Element> *aux;
aux = rearSentinel->getPrevious();
rearSentinel->setPrevious(new_node);
aux->setNext(rearSentinel->getPrevious());
delete aux;
}
num_elements++;
}
template <class Element>
void LinkedDeque<Element>::deleteFront(){
if(!isEmpty()){
if(num_elements == 1){
delete frontSentinel->getNext();
frontSentinel->setNext(rearSentinel);
rearSentinel->setPrevious(frontSentinel);
}else {
Node<Element> *aux;
aux = frontSentinel->getNext();
aux->getNext()->setPrevious(frontSentinel);
frontSentinel->setNext(aux->getNext());
delete aux;
}
num_elements--;
}
}
template <class Element>
void LinkedDeque<Element>::deleteRear(){
if(!isEmpty()){
if(num_elements == 1){
delete rearSentinel->getPrevious();
rearSentinel->setPrevious(nullptr);
frontSentinel->getPrevious(nullptr);
}else{
Node<Element> *aux;
aux = rearSentinel->getPrevious();
aux->getPrevious()->setNext(rearSentinel);
rearSentinel->setPrevious(aux->getPrevious());
delete aux;
}
num_elements--;
}
}
template <class Element>
void LinkedDeque<Element>::print(){
if(!isEmpty()){
Node<Element> *printController = frontSentinel->getNext();
while( printController->getNext()!= nullptr){
cout<< printController->getElement() << endl;
printController = printController->getNext();
}
}
}
template <class Element>
const Element& LinkedDeque<Element>::getFront()const{
return frontSentinel->getNext()->getElement();
}
template <class Element>
const Element& LinkedDeque<Element>::getRear()const{
return rearSentinel->getPrevious()->getElement();
}
#endif /* LINKEDDEQUE_H */
最后是 main.cpp：
#include <cstdlib>
#include"Node.h"
#include"LinkedDeque.h"
using namespace std;
/*
*
*/
int main(int argc, char** argv) {
LinkedDeque<int> *deque= new LinkedDeque<int>;
deque->insertFront(4);
deque->insertFront(5);
deque->insertRear(10);
deque->deleteFront();
deque->print();
}
也许我不应该实现 Node 的析构函数并为它虚拟化？还是指针声明有问题？
【问题讨论】：
-
你是说你的编译器崩溃了？
-
分段错误 (SIG11) 意味着您正在尝试访问分配的地址空间之外的内存。因此，请查找索引到容器、取消引用指针等的问题。
-
小测验：您的构造函数以各种方式取消引用构造对象的类成员
_front、_rear以及其余部分。这些指针指向的对象在哪里？它们在哪里建造？您了解必须使用new等。人。构造具有动态范围的对象。或者，可以在自动范围内声明对象。那么，这些指针所指向的对象是从哪里来的呢？ -
当我试图编译时出现：RUN FINISHED: segment fault:1;实时：10ms...
-
“编译”是什么意思？
标签： c++ c++11 segmentation-fault