内存管理的目的：提高速度，降低空间浪费率

减少malloc的使用。（可以先分配一大块，再一点一点的使用） 较少cookie的使用。

#include 
  
   

using namespace std;

class Screen {
public:
    Screen(int x):i(x) {}
    int get() { return i; }

    void* operator new(size_t);
    void operator delete(void*, size_t);

private:
    Screen* next; // 为了去掉cookie
    static Screen* freeStore;
    static const int screenChunk;
private:
    int i;
};

Screen* Screen::freeStore = 0;
const int Screen::screenChunk = 24; // 创建24份，内存池

void* Screen::operator new(size_t size) {

    Screen* p;
    if (!freeStore) {
        std::cout << "operator new" << std::endl;
        //linked list是空的，所有申请一大块
        size_t chunk = screenChunk * size;
        freeStore = p = reinterpret_cast
   
     (new char[chunk]); //将一大块分割成片，当做linked list串接起来 for (; p!=&freeStore[screenChunk-1]; ++p) { p->next = p + 1; } p->next = 0; } p = freeStore; freeStore = freeStore->next; return p; } void Screen::operator delete(void* p, size_t) { //将deleted object 插入free list前端 (static_cast
    
     (p))->next = freeStore; freeStore = static_cast
     
      (p); } int main() { cout << sizeof(int) << endl; cout << sizeof(Screen) << endl; size_t const N = 100; Screen* p[N]; for (int i = 0; i < N; ++i) { p[i] = new Screen(i); } //输出前10个指针，比较其间隔，确认其没有cookie for (int i = 0; i < 10; ++i) { cout << p[i] << endl; } for (int i = 0; i < N; ++i) { delete p[i]; } return 0; }