C++ 如何使用对象的指针;构造函数和析构函数。C++;

C++ 如何使用对象的指针;构造函数和析构函数。C++;,c++,object,constructor,destructor,C++,Object,Constructor,Destructor,我试图以特定的顺序创建和删除一个对象。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,析构函数从上次创建的对象开始删除。我正在尝试更改输出顺序,类似于以下内容: 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 de

我试图以特定的顺序创建和删除一个对象。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,析构函数从上次创建的对象开始删除。我正在尝试更改输出顺序,类似于以下内容:

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;
};  

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,我正在尝试在删除第三个对象之后删除第二个对象

您使用的
delete
无效,导致未定义的行为,因为您没有使用
new
创建对象。如果您试图销毁堆栈上存在的对象,并且这些对象在超出范围时会自动销毁,则您无权手动销毁它们

如果要使用
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,只需更多地控制对象的范围,而不使用
new
delete
即可获得相同的输出:

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!
void TestObjects()
{
对象obj1(1);
{
对象obj2(2);
对象obj3(3);

}//你的程序表现出不明确的行为,并且可能会在许多C++实现中崩溃。你只能“代码>删除<代码> >你<代码>新< /代码> ED。没有例外的规则。是的,我忘了,谢谢。那么我如何控制对象的创建和删除?”斯坦利我在我的答案中覆盖了这个。再重新阅读一遍。小心
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!