Question

在我的CST类中，我们正在学习C ++中的堆内存。请记住，这是代码应该如何编写（必须使用没有std :: vector或类似的有用类）。下面是我写给我的作业的代码，我通过Visual Studio测试它是否有内存泄漏，并返回：

{173} normal block at 0x008BF658, 257 bytes long.
Data: <                > 00 CD CD CD CD CD CD CD CD CD CD CD CD CD CD CD

这一行：names[i] = new char[257];

但稍后我会将其删除：delete [] names[i];

不知道为什么这不起作用。这是我的代码，包含一个简单的递归函数和main：

#include "stdafx.h"
#include <iostream>
#include <iomanip>
#include <fstream>
#include "CST126SRS02.h"

#define _CRTDBG_MAP_ALLOC  
#include <stdlib.h>  
#include <crtdbg.h>  


using namespace std;


void reverseNames(int &numNames, char ** &names, char ** &temp)
{
    //get names from user, put names in ragged array
    names = new char * [numNames] {};
    int i = 0;
    while (i < numNames) {
        //add name to ragged array
        if (cin.peek() == '\n' && i != 0) break; //make sure there are names
        if (!cin.good()) return; //end of file or errors 

        names[i] = new char[257];
        cin >> setw(256) >> names[i];
        i++;

        if (i == numNames) {
            //need a bigger array, reallocation
            numNames *= 2;

            temp = new char *[numNames] {};
            for (int j = 0; j < numNames / 2; j++)
            {
                temp[j] = names[j];
            }

            delete[] names;
            names = temp;
        }
    }

    //output names in reverse order
    for (int i = numNames - 1; i >= 0; i--) {
        if (names[i] != nullptr) cout << names[i] << " ";
        delete [] names[i]; //also deletes temp items!
    }
    delete [] names; //also deletes temp array!
    cout << endl;

    //recursion
    numNames = 1;
    reverseNames(numNames, names, temp);
}

int main()
{
    //_CrtSetDbgFlag(_CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF);
    //_CrtSetBreakAlloc(173);

    int numNames = 1;
    char **names;
    char ** temp;

    //recursive function, runs until user ends file
    reverseNames(numNames, names, temp);

    delete [] names;

    _CrtDumpMemoryLeaks();

    return 0;
}

内存泄漏在哪里？任何帮助表示赞赏。谢谢！

Answer 1

内存泄漏检测该行将内存泄漏信息输出到输出窗口。

_CrtSetDbgFlag(_CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF);

获取paranthesis中的值并插入下面的这一行（183,184,150）。然后应用程序将在内存分配时中断泄漏，您可以通过调用堆栈追溯。

_CrtSetBreakAlloc(Your value);

专门为此线程添加信息：

char** array = new char*[size]; //This is an array of pointers.
for(int i=0; i<size;i++) { array[i] = new char(); } // Each element in the array creates an object.

要删除：

for(int i=0; i<size; i++){ delete array[i]; } //delete the objects.
delete[] array; //delete the array.

Answer 2

如果发生这种情况，names变量将泄漏。

if (!cin.good()) return; //end of file or errors

准确地说，在这种情况下，new char[257];将不会在返回时被解除分配。

需要帮助找到内存泄漏

2 个答案: