vector压入对象指针

vector压入对象指针(A *)时, 内存不会托管，若对象A在堆上申请空间，需要手动delete ，避免内存泄露

1 错误使用情况, 没有析构A

class A
{
public:
    A()
    {
        cout<<"A():"<<this<<endl;
    }
    A(int i):_data(i)
    {
        cout<<"A(i):"<<this<<endl;
    }
    A(const A & other)
    {
        cout<<"const A & other : "<<this<<" from "<<&other<<endl;
    }
    A& operator=(const A & other)
    {
        cout<<"operator= : "<<this<<" from "<<&other<<endl;
    }
    ~A()
    {
        cout<<"~A(): "<<this<<endl;
    }
private:
    int _data;
};

int main()
{
    vector <A *> res;
    res.reserve(5);
    res.push_back(new A);
    return 0;
}

运行结果：
A():0x781158

2 正确使用

int main()
{
    vector <A *> res;
    res.reserve(5);
    A *pa = new A;
    res.push_back(pa);
    delete pa;
    return 0;
}

运行结果：
A():0x781158
~A(): 0x781158