Question

我尝试运行时，代码中出现访问冲突错误。该程序是一个优先级队列，它插入一个值并在每次插入和最小提取后打印堆。

标题文件：

#pragma once
/*
Header file for the priority queue class
*/
#ifndef PRIORITYQUEUE_H
#define PRIORITYQUEUE_H

class priorityQueue
{
private:
    int size;
    int *data;

public:
    static const int CAPACITY = 50;
    priorityQueue();//constructor
    ~priorityQueue();//destructor
    int getParent(int index);
    int getLeftChild(int index);
    int getRightChild(int index);
    void swap(int &, int &);
    void insert(int item); //enqueue - heap_insert
    void printArray(int []);
    void heapify(int index);

    //remove and return the smallest item currently in the priority queue
    int extractMin();//dequeue 
    bool empty() const;
    int min() const; //return the smallest item
};
#endif

主要代码：

#include <iostream>
#include "priorityQueue.h"
using namespace std;




int main()
{
    priorityQueue myqueue; //class object

    if (myqueue.empty())
        cout << "My priority Queue is empty\n" << endl; //prompt

    myqueue.insert(59); //Insert value into queue
    cout << "After inserting 59 Priority Queue has" << endl;

    myqueue.insert(41);
    cout << "After inserting 41 Priority Queue has" << endl;

    myqueue.insert(25);
    cout << "After inserting 25 Priority Queue has" << endl;

    myqueue.insert(12);
    cout << "After inserting 12 Priority Queue has" << endl;

    myqueue.insert(91);
    cout << "After inserting 91 Priority Queue has" << endl;

    myqueue.min();
    myqueue.extractMin();
    cout << "After extracting the minimum value Priority Queue has" << endl;


    myqueue.insert(34);
    cout << "After inserting 34 Priority Queue has" << endl;

    myqueue.insert(63);
    cout << "After inserting 63 Priority Queue has" << endl;

    myqueue.extractMin();
    cout << "After extracting the minimum value Priority Queue has" << endl;

    myqueue.insert(75);
    cout << "After inserting 75 Priority Queue has" << endl;

    myqueue.insert(85);
    cout << "After inserting 85 Priority Queue has" << endl;

    myqueue.extractMin();
    cout << "After extracting the minimum value Priority Queue has" << endl;




    cout <<"Minimum value is " ; 
    cout << myqueue.min() <<endl; //prints out heap min

    system("pause");
    return 0;
}
priorityQueue::priorityQueue() //constructor
{
    size = CAPACITY;
    &data[size];
}

priorityQueue::~priorityQueue() //destructor
{

}

int priorityQueue::getParent(int index) //finds parent
{
    return (index - 1) / 2;
}

int priorityQueue::getLeftChild(int index) //finds left child
{
    return (2 * index) + 1;
}

int priorityQueue::getRightChild(int index) //find right child
{
    return (2 * index) + 2;
}

void priorityQueue::swap(int& item1, int& item2) //swaps value of two variables
{

    int temp = item1;
    item1 = item2;
    item2 = temp;
}

void priorityQueue::heapify(int index) //heapifies the heap
{
    int largest = index;
    int l = getLeftChild(index);
    int r = getRightChild(index);

    if (l < size && data[l] > data[index])
    {
        largest = l;
    }

    if (r < size && data[r] > data[largest])
    {
        largest = r;
    }

    if (largest != index)
    {
        swap(data[index], data[largest]);
        heapify(data[size]);
    }


}

void priorityQueue::printArray(int []) //prints array
{
    for (int i = 0; i < CAPACITY; i++)
    {
        cout << data[i] << ", ";
    }
}

int priorityQueue::extractMin() //finds min and removes it
{
    int min = data[0];
    data[0] = data[size - 1];
    size - 1;
    heapify(data[size]);
    return min;
}

int priorityQueue::min() const // finds min
{
    return data[0];
}

bool priorityQueue::empty() const // checks if heap is empty
{
    if (data == NULL)
    {
        return true;
    }
    else
    {
        return false;
    }
}

void priorityQueue::insert(int Item) //inserts values into heap
{
    size += 1;
    int i = size - 1;
    while (i > 0 && data[getParent(i)] < Item)
    {
        data[i] = data[getParent(i)];
        i = getParent(i);
    }
    data[i] = Item;
}

Answer 1

在构造函数中，&data[size];什么都不做。你需要为它分配一些内存，可能使用new - data = new int[size] - 或使用智能指针。

调试优先级队列程序时出现访问冲突错误

1 个答案: