访问冲突读取位置0xCDCDCDD1

Question

我正在使用Visual Studio 2013.我收到Access violation reading location 0xCDCDCDD1错误。来自Wikipedia: Magic Numbers，here和this question的引用告诉我，我使用的是未初始化的指针。我认为问题在于我正在使用的malloc函数，尽管在使用之前我确实参考过CPlusPlus文档。

我的代码：

#include "SingleNode.h"
#include "SingleList.h"
#include <iostream>
SingleList::SingleList() {}
SingleList::~SingleList() {}
...
    void SingleList::addHead(int value){
    ISingleNode *temp1 = (ISingleNode *)malloc(sizeof(SingleList));
    head = NULL;
    temp1->setValue(value);
    temp1->setNext(head->getNext());
    if (!head->getNext())
    {
        head = temp1;
    }
    else
    {
        temp1->setNext(head->getNext());
        head = temp1;
    }
}

    ...

错误在第temp1->setValue(value);行

中

此处包含setValue(int value)功能：

#include "SingleNode.h"
SingleNode::SingleNode() {}
SingleNode::~SingleNode() {}
void SingleNode::setValue(int value){
    this->value = value;
}
int SingleNode::getValue(){
    return value;
}
ISingleNode * SingleNode::getNext(){
    return next;
}
void SingleNode::setNext(ISingleNode * next){
    this->next = next;
}

SingleNode.h：

#pragma once
#include "Interfaces01.h"
class SingleNode :public ISingleNode{
private:
    int value;
    ISingleNode * next = NULL;
public:
    SingleNode();
    ~SingleNode();
    void setValue(int value);
    int getValue();
    ISingleNode * getNext();
    void setNext(ISingleNode * next);
};

SingleList.h：

#pragma once
#include "Interfaces01.h"
class SingleList :public ISingleList{
private:
    int value;
    ISingleNode * head=NULL;
    ISingleNode * temp=NULL;
    ISingleNode * next=NULL;
    ISingleNode * temp1;
public:
    SingleList();
    ~SingleList();
    ISingleNode * getHead();
    void setHead(ISingleNode * head);
    void addHead(int value);
    void orderSort2();
    void orderSort3();
    void sequenceOrderSort();
    void reverse();
    ISingleNode * swap(ISingleNode * head, int k);
    ISingleNode * get_node(ISingleNode * head, int k);
};

在断行时，调试器显示以下值：

Answer 1

1. 变化：

   ISingleNode *temp1 = (ISingleNode *)malloc(sizeof(SingleList));
   

   成：

   ISingleNode *temp1 = new SingleList;
   

2. 您正在访问NULL指针：

   head = NULL; // set to NULL
   temp1->setValue(value);
   temp1->setNext(head->getNext()); // oops!
   

   你可能意味着：

   void SingleList::addHead(int value)
   {
       ISingleNode *temp1 = new SingleList;
       temp1->setValue(value);
       temp1->setNext(head);
       head = temp1;
   }