Question

我对C ++内存管理很陌生，因为与C不同，释放所有内存还有更多障碍。

我试图成功删除指向任何类型矢量的指针（即矢量*数据）

/** 
 * We test the program in accessing vectors
 * with dynamic storage
**/
#include <iostream>
#include <vector> // you must include this to use vectors

using namespace std;

int main (void){
    // Now let's test the program with new and delete
    // for no memory leaks with vectors (type safe)
    // however, just calling delete is not enough to free all memory
    // at runtime
    vector <int> * test_vect = new vector <int> (10,5);

    // Print out its size
    cout << "The size of the vector is " << test_vect->size()
         << " elements" << endl;

    // run through vector and display each element within boundary
    for (long i = 0; i < (long)test_vect->size(); ++i){
        cout << "Element " << i << ": " << test_vect->at(i) << endl;
    }

    delete test_vect;
    return EXIT_SUCCESS;
}

但是，使用valgrind

后出现内存泄漏

==2301== HEAP SUMMARY:
==2301==     in use at exit: 4,184 bytes in 2 blocks
==2301==   total heap usage: 4 allocs, 2 frees, 4,248 bytes allocated
==2301== 
==2301== LEAK SUMMARY:
==2301==    definitely lost: 0 bytes in 0 blocks
==2301==    indirectly lost: 0 bytes in 0 blocks
==2301==      possibly lost: 0 bytes in 0 blocks
==2301==    still reachable: 4,096 bytes in 1 blocks
==2301==         suppressed: 88 bytes in 1 blocks

如何通过指向vector的指针（即在运行时）摆脱所有内存泄漏痕迹？

Answer 1

对于初学者，我不相信有泄漏。您是否正确阅读了为该计划发布的Leak Summary？：

==2301== LEAK SUMMARY:
==2301==    definitely lost: 0 bytes in 0 blocks
==2301==    indirectly lost: 0 bytes in 0 blocks
==2301==      possibly lost: 0 bytes in 0 blocks
==2301==    still reachable: 4,096 bytes in 1 blocks
==2301==         suppressed: 88 bytes in 1 blocks

你在0个街区中丢失了0个字节。 valgrind找不到任何确定的，间接的或可能的泄漏。你的程序很好。

暂且不谈： 你......真的不应该在这种情况下使用new或delete。 C ++与C一样，如果将它们声明为常规变量，那么它们就会进入堆栈范围并超出范围。以下代码完全实现了您在问题中所做的操作，而不使用new和delete：

int main (void){
    // Now let's test the program with new and delete
    // for no memory leaks with vectors (type safe)
    // however, just calling delete is not enough to free all memory
    // at runtime (ThePhD: it is, actually!)
    vector <int>  test_vect(10,5);

    // Print out its size
    cout << "The size of the vector is " << test_vect.size() 
         << " elements" << endl;

    // run through vector and display each element within boundary
    for (long i = 0; i < (long)test_vect.size(); ++i){
        cout << "Element " << i << ": " << test_vect.at(i) << endl;
    }

    // ( ThePhD: Look ma, no deletions! )
    return EXIT_SUCCESS;
}

堆栈会神奇地清理它自己，因为std :: vector有一个析构函数，当它超出范围时清理它的资源。您不需要将其设置为动态并将其放在程序存储器的堆/自由存储区域，当堆栈完成时就可以了。

另外，听起来你来自C，所以我会花时间说：欢迎使用C ++。：d

Answer 2

我认为这可以作为答案。就C ++而言，这里没有泄漏。

Answer 3

这些容器类的全部目的是为您执行内存管理，分配，重新分配和释放。您将容器放在堆栈上，它在内部保持动态分配的内容，并在删除容器实例时自动删除动态分配的数据。

容器本身的动态实例化失败了目的，几乎总是毫无意义。

是的，在你的情况下，矢量真的被删除了。

Answer 4

我想你需要打电话

if(test_vect != 0)
{
   if(!test_vect->empty())
      test_vect->clear();
}

删除之前

如何真正删除矢量

4 个答案: