Question

我有一个有序的数组列表。在我的resize函数中，我创建一个新数组并为其分配旧数组的值，然后使用delete[] arrayname;删除旧数组。每当调整大小功能发挥作用时，这会在运行时导致错误。调用dbgheap.c。有没有人见过这个？

这是我的代码：

//--------------------------------------------------------------------------------------------
//  Name:           OrderedArray.h.
//  Description:    Header file for the use in OrderedArray.cpp.
//--------------------------------------------------------------------------------------------
#ifndef ORDEREDARRAY_H
#define ORDEREDARRAY_H
#include <iostream>

using namespace std;
//--------------------------------------------------------------------------------------------
//  Name:           template <class Datatype>   
//  Description:        
//--------------------------------------------------------------------------------------------
template <class Datatype>
//--------------------------------------------------------------------------------------------
//  Class: OrderedArray.            
//--------------------------------------------------------------------------------------------
class OrderedArray
{
//--------------------------------------------------------------------------------------------
//  Member Variables.           
//--------------------------------------------------------------------------------------------
private:
Datatype* m_array;
int size;
int g_size;
int num_elements;   //Counter for the number of elements in the Array.

void Resize(int p_size)//resizes the array to the size of p_size
    {
        cout << "Did i get this far ";
        if(p_size < 0)//checks if new size is less than 0
        {
            cout << "ERROR! Size of an array can not be less than 0!" << endl;
        }
        else//else its ok to continue
        {
            Datatype* newArray = new Datatype[p_size];//creates a pointer newArray that points at a new array
            if(newArray == 0)
            {
                return;
            }
            cout << "Did i get this far ";
            int min;

            if(p_size < size)//checks the if the new array is smaller than the old one
                min = p_size;
            else//else its going to be bigger
                min = size;
            cout << "Did i get this far ";
            int index;
            int temp = num_elements;//puts num_elements into a temporary variable called temp
            num_elements = 0;//num_elements is set to 0
            for(index = 0; index < min; index++)
            {
                newArray[index] = m_array[index];//places everything from the old array into the new array that will fit.
                if(num_elements < temp)//if the num_elements is less than temp(the original num_elements)
                {
                    num_elements++;//increment num_elements. This will keep incrementing to create the new num_elements based the number of elements cut off in the resize
                }
            }
            size = p_size;//sets the old size to be equal to the new size
            cout << "Did i get this far ";
            if(m_array != 0)
            {
            cout << "\nI am just about to delete ";
            delete[] m_array;//deletes the old array
            }
            m_array = newArray;//makes m_array point at the new array
            newArray = 0;//makes newArray a null pointer
        }
    }
//---------------------------------------------------------------------------------------
// Name:             Push
// Description:      
//---------------------------------------------------------------------------------------
void push(Datatype p_item)
{
    if(num_elements == size)//checks if the array is full and needs to be resized
    {
        Resize(size + g_size);//calls the resize function
    }

    int pos = num_elements;
    for(int x=0;x<num_elements;x++)
    {
        if(p_item < m_array[x])
        {
        pos=x;
        }
    }

    //loops through the array from high to low moving all values to the right
    //to make space for the passed in value until it gets to the right place
    for(int index = num_elements; index >= pos; index--)
    {
        m_array[index] = m_array[index-1];//moves the values to the right
    }
        m_array[pos] = p_item;//the passed in value is positioned into its ordered position
        num_elements++;

    cout<< "Num Elements " << num_elements;
    cout<< "Size " <<size;
}

    //--------------------------------------------------------------------------------------------
    //  Name:           Constructor.
    //  Description:    Constructs the Array.
    //--------------------------------------------------------------------------------------------
    OrderedArray(int p_size, int grow_size)
    {
        //Sets the Array size.
        m_array = new Datatype[p_size,grow_size];   
        size = p_size;
        g_size = grow_size; 
        //How many elements are in the Array.
    num_elements = 0;               
}

// size和g_size由程序开头的用户给出它的值。

Answer 1

这里可能还有其他问题，但我能看到的最明显的事情就是：

for(int index = num_elements; index >= pos; index--)
{
    m_array[index] = m_array[index-1];
}

如果pos恰好为零，您最终会这样做：

    m_array[0] = m_array[-1];

此问题会立即显示（当num_elements为零时 - 您尚未显示构造函数，但我希望您初始化所有内容）。

在循环中将>=更改为>可能会解决您的所有麻烦。

从概念上讲，你应该同意这个逻辑。当您要将 m_array[pos]前的项目 m_array[pos]转发到m_array = new Datatype[p_size,grow_size];时，无法将该项目替换为新项目。

[edit] 现在您已经发布了构造函数：

grow_size

由于逗号运算符的工作方式，这将使用p_size而不是m_array = new Datatype[p_size];初始化数组。阅读：How does the Comma Operator work

请改为：

{{1}}

Answer 2

构造函数中的代码m_array = new Datatype[p_size,grow_size];应该只接受一个与数组大小相同的参数。

更改为：m_array = new Datatype[p_size];

删除数组会导致运行时错误。 C ++

2 个答案: