创建一个列C的深层副本++ [英] Create a deep copy of an array C++

问题描述

我试图解决我的程序有些问题，这似乎是有或者是与我的拷贝构造函数或析构函数的问题。我得到一个内存异常。

任何帮助将我AP preciated
谢谢

  ArrayStorage :: ArrayStorage（常量ArrayStorage＆安培; A）：readArray（a.readArray），ARRAYSIZE（a.arraysize）
{
    readArray =新的字符串[ARRAYSIZE] //创建数组    的memcpy（readArray，a.readArray，的sizeof（字符串）* ARRAYSIZE）; //复制字节的值从该位置指向由烃源和目的地。
}ArrayStorage ::〜ArrayStorage（无效）
{
    删除[]（readArray）; // deconstuctor删除阵列。
}
 

这会是一个更好的方式比其他的memcpy数组复制：

 的for（int i = 0; I＆LT; ARRAYSIZE;我++）
    {
        readArray [I] = a.readArray [I]
    }
 

解决方案

您不能只是的memcpy 随机对象，你需要真正用自己的复制操作复制它们。

字符串最有可能拥有一个指向堆分配存储。如果你把它复制位运算，要求原始字符串析构函数的无效复制字符串的数据。

使用类似的std ::复制正确做到这一点。

 的#include＆LT;＆算法GT;
...
性病::复制（a.readArray，a.readArray + ARRAYSIZE，readArray）;
 

I am try to solve some problems in my program and it would appear that there is either a problem with my copy constructor or with my destructor. I am getting a memory exception.

any help would me appreciated Thanks

ArrayStorage::ArrayStorage(const ArrayStorage &a):readArray(a.readArray),arraysize(a.arraysize)
{
    readArray = new string[arraysize]; //create the array

    memcpy (readArray,a.readArray,sizeof(string)*arraysize);//Copy the values of bytes from the location pointed at by the souce and destination.
}

ArrayStorage::~ArrayStorage(void)
{
    delete[](readArray);//deconstuctor to delete the array.
}

would this be a better way to copy the array other than memcpy :

for (int i = 0 ; i < arraysize ; i ++)
    {
        readArray[i] = a.readArray[i];
    }

解决方案

You can't just memcpy random objects, you need to actually copy them with their copy operators.

string most likely holds a pointer to heap-allocated storage. If you copy it bitwise, calling the destructor on the original string invalidates the "copied" string's data.

Use something like std::copy to do this properly.

#include <algorithm>
...
std::copy(a.readArray, a.readArray+arraysize, readArray);

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