Placement New 实现自Effective C++ Item4

#include <iostream>using namespace std;class EquipmentPiece{public:    EquipmentPiece(int IDNumber)    {        this->IDNumber = IDNumber;    }    void PrintOut()    {        cout << IDNumber << endl;    }private:    int IDNumber;};int main(){    // 为大小为 10 的数组 分配足够的内存    // EquipmentPiece 对象;    // operator new[] 函数    char *rawMemory = new char[10*sizeof(EquipmentPiece)];    // 或者void *rawMemory = operator new[](10*sizeof(EquipmentPiece));    //  EquipmentPiece *bestPieces = static_cast<EquipmentPiece*>(rawMemory);    // make bestPieces point to it so it can be treated as an    // EquipmentPiece array    EquipmentPiece *bestPieces = reinterpret_cast<EquipmentPiece*>rawMemory;    // construct the EquipmentPiece objects in the memory    // 使用"placement new"    for (int i = 0; i < 10; ++i)        new (&bestPieces[i]) EquipmentPiece(i);    for (int i = 0; i < 10; ++i)        bestPieces[i].PrintOut();    // 以与构造 bestPieces 对象相反的顺序    // 解构它。    for (int i = 9; i >= 0; --i)        bestPieces[i].~EquipmentPiece();    // deallocate the raw memory    delete[]rawMemory;    return 0;}