C++ 使用链表实现错误队列

我试图使用链表实现队列，但它意外地停止了。 找不到原因

#include <iostream>
#include <string>

using namespace std;

包含队列操作的队列类

class Queue{
private:
    Node* front = NULL;
    Node* rear = NULL;
public:
    void enQueue(int x){
    Node* temp = NULL;
    temp->data = x;
    temp->next = NULL;
    if(front == NULL && rear == NULL){
        front = rear = NULL;
        return;
    }
    rear->next = temp;
    rear = temp;
    }
    void dequeue()
    {
        Node* temp = front;
        if(front == NULL)
        {
            cout << "No list found." << endl;
            return;
        }
        if(front == rear){
            front = rear = NULL;
        }
        else{
            front = front->next;
        }
        delete temp;
    }
};

---

第一次将节点排入队列时，将取消对空指针的引用

void enQueue(int x){
    Node* temp = NULL;
    temp->data = x; // Wrong

取消对空指针的引用会产生错误

您正在分配给一个无效的地址

---

这只会阻止程序“意外停止”。但是仍然存在错误。

您的排队函数中有一个错误。进行以下更改：

void enQueue(int x){
    Node* temp = new Node();//you need to create this variable and not set it to NULL
    temp->data = x;
    temp->next = NULL;
    if(front == NULL && rear == NULL){
        front = rear = temp;
        return;
    }
    rear->next = temp;
    rear = temp;
    }

现在，您的程序将按预期运行

void enQueue(int x){
    Node* temp = NULL;
    temp->data = x; // Wrong

void enQueue(int x){
  Node* temp = NULL;   //Node* temp = new Node;
  temp->data = x;      //BOOM
  temp->next = NULL;
  if(front == NULL && rear == NULL){
    front = rear = NULL;  //What?
    return;
  }
  rear->next = temp;
  rear = temp;
}

void enQueue(int x){
    Node* temp = new Node();//you need to create this variable and not set it to NULL
    temp->data = x;
    temp->next = NULL;
    if(front == NULL && rear == NULL){
        front = rear = temp;
        return;
    }
    rear->next = temp;
    rear = temp;
    }