编码动态数组C++时出现内存异常

Question

我对 c++ 相当陌生，因为这是我上的第一堂课。 我正在创建一个类，该类将根据执行的操作动态创建/删除数组。 当我尝试向我相信的数组添加某些内容时，我会收到此异常。 任何帮助都非常感谢。

法典：

#include "ArrayList.h"
#include < string>
using namespace std;
int count = 0;
 ArrayList::ArrayList(){
Object *items = new Object[count];
items[0] = "NULL";
}    
 ArrayList::~ArrayList(){
 releaseList();
 }
void ArrayList::releaseList(){
delete[] items;
count = 0;
ArrayList();
}
void ArrayList::add(Object o){
Object *temp = new Object[count + 1];
for(int i = 0; i < count; i ++){
    temp[i] = items[i];
}
temp[count + 1] = o;
delete[] items;
items = temp;
delete[] temp;
count = count + 1;
}
void ArrayList::add(Object o, int index){
Object *temp = new Object[count + 1];
for(int i = 0; i < index; i++){
    temp[i] = items[i];
}
temp[index] = o;
for(int i = index + 1; i < count -1; i ++){
    temp[i] = items[i];
}
delete[] items;
items = temp;
delete[] temp;
count = count + 1;
}

ArrayList 的 .h 文件

#ifndef ARRAY_LIST_H
#define ARRAY_LIST_H
#include <string>
using namespace std;
typedef string Object;

class ArrayList {
private:
Object *items;      // a dynamic array of pointers to Objects
int numberOfItems;
// Releases all the memory allocated to the list; resets the object to its
// default values.
void releaseList();
public:
// Initializes object to default values (NULL, 0).
ArrayList();
// Destroys the object. Calls releaseList() to do the actual work.
~ArrayList();
// Appends the object o to the end of the list. This resizes the array by 1.
void add(Object o);
// Adds the object o and the specified index. This resizes the array by 1.
void add(Object o, int index);
// Removes all the items from the list. Resets object to its default state.
void clear();
// Returns true if the list contains the object o.
bool contains(Object o) const;
// Returns the object at the specified index. Assumes index is in range.
Object objectAt(int index) const;
// Returns the index of the first matching object o. Assumes the object is in the list.
int indexOf(Object o) const;
// Returns the index of the last matching object. Assumes the object is in the         list.
int lastIndexOf(Object o) const;
// Returns true if list is empty.
bool isEmpty() const;
// Removes the object o from the list. List is resized. Assumes object is present.
void remove(Object o);
// Removes the object o at the specified index. List is resized. Assumes index is in range.
void remove(int index);
// Returns the number of elements in the list.
int size() const;
// Sets the element at the specified index.
void set(Object o, int index);
// Returns a string containing all the items comma separated and surrounded
// by curly ({) braces, i.e. {item1, item2, ...}
string toString();
};
#endif

Answer 1

这是一个问题，在 ArrayList::add 中，将引发访问冲突异常：

Object *temp = new Object[count + 1];
...
temp[count + 1] = o;

您正在将对象分配给数组末尾之后的内存位置。 C++是零索引的，这意味着如果你有

int A = new int[5];

则有效位置A[0]... A[4]，但不是A[5]。