删除动态数组？ [英] Deleting dynamic arrays?

问题描述

我有关于我的项目中删除动态数组的问题。

I'm having problems about deleting dynamic arrays in my project.

第一次出现：

void StudentReviewSystem::addCourse( const int courseId, const string courseName )
{
    int i = findCourse( courseId );

    if ( i == -1 )
    {
        int newNum = numberOfCourses + 1;
        Course *newCourses = new Course[newNum];
        for ( int j = 0; j < numberOfCourses; j++ )
        {
            newCourses[j] = courses[j];
        }
        Course aCourse(courseId, courseName);
        newCourses[numberOfCourses] = aCourse;
        //delete[] courses;
        courses = newCourses;
        numberOfCourses = newNum;
        cout<< "Course "<< courseId <<" has been added."<< endl;
    }
    else
    {
        cout<< "Course "<< courseId <<" has already exist."<< endl;
    }
}

课程是在我的头中定义一个指针。
如果我注释掉删除行，code的作品就好，否则，程序崩溃。

courses is a pointer which was defined in my header. If I comment out the delete line, code works just fine, otherwise, program crashes.

另一个显示：

StudentReviewSystem::StudentReviewSystem()
{
    numberOfCourses = 0;
    courses = new Course[0];
}

StudentReviewSystem::~StudentReviewSystem()
{
    //delete[] courses;
}

我知道我必须删除我的动态数组以避免内存泄漏，但每当我的析构函数被调用，程序崩溃，所以我注释掉该行也。

I know I must delete my dynamic arrays to avoid memory leaks, but whenever my destructor is called, program crashes so I comment out that line too.

每当我尝试删除一个动态数组，程序崩溃，无论我做什么。

Whenever I try to delete a dynamic array, program crashes no matter what I do.

原来，你不是能删除[] 与大小为0阵列所以，我想每一次检查大小删除的数组。但是做了0大小的数组导致内存泄漏？

It turned out that you can't delete[] an array with size 0. So, I check for size every time I want to delete an array. But does a 0 size array causes memory leak?

推荐答案

如果您的类管理资源，那么你通常需要析构函数，拷贝构造函数和拷贝赋值运算符，每的 /stackoverflow.com/questions/4172722\">Rule。我的猜测是，你没有这些，所以班里有无效的复制语义：复制将刚才复制的指针，而不是动态数组，留下两个对象都想要删除同一阵列

If your class manages resources, then you usually need a destructor, copy-constructor, and copy-assignment operator, per the Rule of Three. My guess is that you don't have these, so the class has invalid copy semantics: copying it will just copy the pointer, not the dynamic array, leaving two objects both wanting to delete the same array.

无论是执行或删除复印功能，或者更好，是不管理的资源自己：使用的std ::矢量＆lt;场＆GT; 做的工作您。您不需要析构函数或者如果你这样做，而 addCourse 就会简单得多。

Either implement or delete the copy functions, or (better still) don't manage the resources yourself: use std::vector<Course> to do the work for you. You won't need the destructor either if you do that, and addCourse would be much simpler.

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