分配并释放一系列杠杆2指针？ [英] Allocate and free an array of lever 2 pointer?

问题描述

我有一个杠杆2指针阵列** f [5] - > f [5] [6] [7]，我想将它们分配给堆内存然后释放它们，怎么做？谢谢。



我这样做会导致内存泄漏：

- 分配它们：

I have an array of lever 2 pointer **f[5] -> f[5][6][7], I want to allocate them on Heap memory and then free them, how to do this? Thanks.

I get memory leak when I do it:
- Allocate them:

for (int i=0;i<5;i++)
{
     f[i]= new int*[6];
     for (int j=0;j<6;j++)
         f[i][j]= new int[7];
}

并将它们释放如下：

And free them as follows:

for (i=0;i<6;i++)
     delete[] f[i];

我的完整代码如下：

My full code is as follows:

// a.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"


int _tmain(int argc, _TCHAR* argv[])
{
    int i, j;
    int **f[5];   // f[5][6][7]
    for (i=0;i<5;i++)
    {
         f[i]= new int*[6];
         for (j=0;j<6;j++)
             f[i][j]= new int[7];
    }
    for (i=0;i<5;i++)
        for (j=0;j<6;j++)
            for (int k=0;k<7;k++)
                f[i][j][k]=i*j*k;
    for (i=0;i<5;i++)
    {
         for (j=0;j<6;j++)
             delete[] f[i][j];
         delete[] f[i];
    }


    return 0;
}

我收到两个警告（我的项目名称是a）：

And I get two warnings (the name of my project is "a"):

Warning	1	warning C6211: Leaking memory 'f[0]' due to an exception. Consider using a local catch block to clean up memory: Lines: 9, 10, 12, 13, 14	c:\users\peter\desktop\a\a\a.cpp	12	a

Warning	2	warning C6211: Leaking memory 'f[0][8]' due to an exception. Consider using a local catch block to clean up memory: Lines: 9, 10, 12, 13, 14, 13, 14, 13, 14, 13, 10, 12	c:\users\peter\desktop\a\a\a.cpp	14	a

我不明白他们。你能帮我检查一下吗？谢谢。

I dont understand them. Can you help me check it. Thanks.

推荐答案

首先，你正在使用立即常量 5,6和7.即使你没有错误，它也是'这是绝对不可接受的，因为它使你的代码完全不受支持。您只需要两个常量：内部数组维度和数组数组的维度;并且你必须明确地声明它们。



现在，没有显示解决方案（请自己做;只有在这种情况下你才能学会做某事），我''会告诉你明显的错误：



你在两个嵌套循环中进行分配。在外循环中，你调用运算符 new 5次，在内循环中，你在每次迭代中执行6次，所以你调用运算符新的（6 + 1）* 5 =共35次。

当你进行释放时，你打电话给 delete [] 在一个循环中，6次。难怪你有内存泄漏。



现在，想一想并解决它。如果很难想象，在纸上绘制分配的内存区域并编写代码。这真的很容易。



祝你好运，

-SA

First of all, you are using immediate constants 5, 6 and 7. Even if you had no bugs, it''s absolutely unacceptable, as it makes your code totally unsupportable. You need only two constants: the inner array dimension, and the dimension of the array of arrays; and you have to declare them explicitly.

Now, without showing a solution (please do it by yourself; only in this case you can learn to do something), I''ll show you the apparent bug:

You do allocation in two nested loops. In outer loop, you call the operator new 5 times, in inner loop, you do it 6 times in each iteration, so you call call the operator new (6 + 1) * 5 = 35 times altogether.
When you do deallocation, you call delete[] in a single loop, 6 times. No wonder you have a memory leak.

Now, think just a bit and fix it. If it''s hard to imagine, draw the allocated memory area on paper and write the code. This is really easy.

Good luck,

—SA

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