Effective C++ Placement new

 1 #include <iostream>

 2 #include <cstdlib>

 3 

 4 using namespace std;

 5 

 6 class Card {

 7     private:

 8         int m_SerialNumber;

 9     public:

10         Card(int id) : m_SerialNumber(id) {}

11         ~Card() {cout<<"~Card"<<endl;}

12         void print() {cout<<m_SerialNumber<<endl;}

13 };

14 

15 int main() {

16     int num = 10;

17     void *rawMemory = operator new[](num * sizeof(Card));

18     Card *cards = static_cast<Card*>(rawMemory);

19     

20     for (int i=0; i<num; i++) {

21         new(&cards[i]) Card(i+1);

22     }

23     

24     for (int i=0; i<num; i++) {

25         cards[i].print();

26     }

27     

28     for (int i=num-1; i>=0; i--) {

29         cards[i].~Card();

30     }

31     operator delete[](rawMemory);

32     system("pause");

33     return 0;

34 }

这么奇葩的操作。

 operator delete[] 只能对由对应 operator new[] 得到的空间指针变量操作，不能直接对cards指针使用