我正在尝试以特定的顺序输出对象的创建和删除。默认情况下,首先使用构造函数析构函数创建第一个对象,依此类推,然后析构函数开始从最后创建的对象中删除。我正在尝试更改输出顺序,如下所示:
Object 1 is created, we've got 1 object(s) now!
Object 2 is created, we've got 2 object(s) now!
Object 3 is created, we've got 3 object(s) now!
Object 3 is deleted, we've got 2 object(s) now!
Object 2 is deleted, we've got 1 object(s) now!
Object 4 is created, we've got 2 object(s) now!
Object 4 is deleted, we've got 1 object(s) now!
Object 1 is deleted, we've got 0 object(s) now!
代码:
class Object {
public:
Object(int i) {
id = i;
count++;
cout<<"Object "<<id<<" is created, we've got "<<count<<" object(s) now!"<<endl;
}
~Object() {
count--;
cout<<"Object "<<id<<" is deleted, we've got "<<count<<" object(s) now!"<<endl;
}
private:
int id;
static int count;
};
为了做到这一点,我发现我可以使用指针,指向创建的对象,并在我们想要的时候删除,这样我们就可以控制创建和删除的顺序。
#include"Object.h"
extern void TestObjects()
{
Object *a;
Object obj1(1),obj2(2),obj3(3);
a = &obj3;
delete a;
Object *c;
c = &obj2;
delete c;
}
到目前为止,它只创建了3个对象,并在创建后立即删除了第三个对象,我正在尝试删除第三个对象之后的第二个对象。
发布于 2019-03-20 09:00:52
您对delete
的使用无效,从而导致未定义的行为,因为您没有使用new
创建对象。您正在尝试销毁堆栈上存在的对象,并在它们超出范围时自动销毁,您无权手动销毁它们。
如果您想使用delete
控制销毁顺序,则必须使用new
,如下所示:
void TestObjects()
{
Object *obj1 = new Object(1);
Object *obj2 = new Object(2);
Object *obj3 = new Object(3);
delete obj3;
delete obj2;
Object *obj4 = new Object(4);
delete obj4;
delete obj1;
}
或者,在您的特定示例中,可以通过简单地更多地控制对象的作用域而完全不使用new
和delete
来获得相同的输出:
void TestObjects()
{
Object obj1(1);
{
Object obj2(2);
Object obj3(3);
} // <-- obj3 and obj2 are destroyed here, in that order!
Object obj4(4);
} // <-- obj4 and obj1 are destroyed here, in that order!
https://stackoverflow.com/questions/55252087
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