Question

每当我在程序中运行任何函数（插入并显示，由于无法插入而无法确定是否删除），我似乎总是收到“ Segmentation Error：11”。我不太确定这是什么意思，或者从哪里开始寻求修复。任何帮助将不胜感激从哪里开始。我了解到，这与内存有关，从我发现的情况来看，这可能意味着某件事占用了太多内存。

#include <iostream>
#include <cstring>
#include <cstdlib>
#include "priority_queue.h"
//#include <heap.h>

using namespace std;

struct node{
    int priority;
    int info;
    struct node* link;
};

class PriorityQueue{
private:
    node* front;
public:
    void Priority_Queue(){
        front = 0;
    }
    void insert(int item, int priority){
        node* temp, *q;
        temp = new node;
        temp->info = item;
        temp->priority = priority;
        if(front == 0 || priority < front->priority){
            temp ->link = front;
            front = temp;
        }
        else{
            q = front;
            while(q->link != 0 && q->link->priority <= priority)
                q = q->link;
            temp->link = q->link;
            q->link = temp;
        }
    }
    void del(){
        node* temp;
        if(front == 0)
            cout << "Underflow" << endl;
        else{
            temp = front;
            cout << "Delete item is: " << temp->info << endl;
            front = front->link;
            free(temp);
        }
    }
    void display(){
        node* ptr;
        ptr = front;
        if(front == 0)
            cout << "Queue is empty" << endl;
        else{
            cout << "Queue is: " << endl;
            cout << "Priority Item" << endl;
            while(ptr != 0){
                cout << ptr->priority << endl;
                ptr = ptr->link;
            }
        }
    }
};
    int main(){
    int choice, item, priority;
    PriorityQueue pq;
    while(1){
        cout << "1. Insert" << endl;
        cout << "2. Delete" << endl;
        cout << "3. Display" << endl;
        cout << "4. Quit" << endl;
        cout << "Enter Choice " << endl;
        cin >> choice;
        switch(choice){
            case 1:
            cout << "Input the item value to be added into the queue" << endl;
            cin >> item;
            cout << "Enter its priority " << endl;
            cin >> priority;
            pq.insert(item, priority);
            break;
            case 2:
            pq.del();
            break;
            case 3:
            pq.display();
            break;
            case 4:
            break;
            default:
            cout << "That is not an option" << endl;
        }
    }
    //while(choice != 4);
        return 0;
    }

Answer 1

问题似乎出在类定义上。正如WhozCraig指出的那样，假定构造函数的名称是错误的，因此它永远不会被调用。更正的代码：

class PriorityQueue {
private:
    node* front;
public:
    PriorityQueue() : front(nullptr) {
    }
};

如果您查看调试器，可能会发现front从未正确初始化。在C ++中，尝试使用nullptr表示“空指针”。在C语言中使用NULL。使用0会产生很多歧义，即使它由于历史原因而“起作用”。

使用优先级队列插入/显示功能时出现细分错误

1 个答案: