对象指针向量返回奇数值 [英] Vector of object pointers returns odd values

问题描述

我有一项任务是创建一个对象 Stos，其中包含一堆对象 Obiekt，我可以随意添加内容.

I have a task to create an object Stos which would feature a heap of objects Obiekt, to which I could add things as I please.

为了让程序更好地支持动态数组，我决定使用 Vector.整个实现似乎完美运行，返回值完全关闭.这是一个带有代码的示例:

In order to make the program better support dynamic arrays I decided to use a Vector. The whole implementation seems to run perfectly, the returned value is completely off. Here is an example with code:

class Obiekt {
private:
    int id;

public:
    Obiekt::Obiekt(int i) {
        id = i;
    }

    void Obiekt::display() {
        cout << "This object has id of: " << id << endl;
    }
};

class Stos {
private:
    vector < Obiekt* > stos;
public:
    Stos::Stos(Obiekt n) {
        add(n);
    }

    void Stos::add(Obiekt n) {
        stos.push_back(&n);
    }

    void Stos::display() {
        cout << endl << "===HEAP DISPLAY===" << endl;
        for (int i = 0; i < stos.size(); i++) {
            stos[i]->display();
        }
    }
};

void Zad1()
{
    Obiekt obj1(5);
    Obiekt obj2(23);

    Stos s1(obj1);
    s1.add(obj2);
    s1.display();

    getchar();
}

结果是:

===堆显示===

此对象的 ID 为:-858993460

This object has id of: -858993460

此对象的 ID 为:9805925

This object has id of:9805925

我不是 cpp 专家，我相信这个问题与 stos.push_back(&n) 部分有关，但我无法捕捉到 id 变得如此扭曲的那一刻.

I'm not a cpp expert, and believe the issue is related to the stos.push_back(&n) portion, but I can't catch the moment the id gets so distorted.

这可能是一个菜鸟问题，所以在开始时很抱歉.

It's probably a noob question, so sorry for that on start.

任何帮助都会很棒.

推荐答案

Obiekt n 中的参数

Stos::Stos(Obiekt n) {
    add(n);
}

void Stos::add(Obiekt n) {
    stos.push_back(&n);
}

是每次调用后立即销毁的临时副本.

are temporary copies destroyed immediatly after each call.

您必须使用参考 Obiekt &n 代替，或者更好:通过指针Obiekt * n.

You have to use a reference Obiekt & n instead, or better: by pointer Obiekt * n.

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