#include <iostream>
using namespace std;

class A{
private:
    int num;
public:
    A(){
        cout << "A's constructor" << endl;
    }

    ~A(){
        cout << "~A" << endl;
    }
    void show(){
        cout << "num:" << num << endl;
    }
};

int main()
{
    char mem[10];
    mem[0] = 'a';
    mem[1] = '\0';
    mem[2] = '\0';
    mem[3] = '\0';
    cout << (void*)mem << endl;
    new(mem) char('b');
    A* p = new(mem) A;
    p->show();
    cout << p << endl;
    cout << (void*)mem << endl;
cout << mem[0];
    return 0;
}

0xffea491e
A's constructor
num:98
0xffea491e
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b