c++ - 我们如何释放已分配的内存 : A& o = *(new A)?

Question

请看下面的程序代码。我已经发表了很多评论来阐明我遇到的问题。

#include <iostream>

class A {
    public:
        void test() {
            std::cout << "foo" << std::endl;
        }
};

int main() {
    A& o = *(new A); // The memory for object "o" is allocated on the heap.
    o.test();        // This prints out the string "foo" on the screen.
                     // So far so good.

    // But how do I now deallocate the memory used by "o"? Obviously,
    // memory has been allocated, but I know of no way to relinquish it
    // back to the operating system.

    // delete o;     // Error: type ‘class A’ argument given to ‘delete’,
                     // expected pointer


    return 0;
}

Answer 1

这条线很奇怪

A& o = *(new A);

考虑改变它。我看不出将其声明为指针有任何好处，A* o = new A(); .

---

如果要释放内存:

delete &o; //Deletes the memory of 'o'

请注意，如果您定义了 o作为

A o = *(new A);

你将没有释放内存的方法，因为那样o将是 A 的拷贝(带有全新地址!)分配。 o会因此在堆栈上创建，所以 delete &o;会导致未定义的行为。