C++ new/delete 重载
首先，new和delete是运算符，重载new和delete是可能的。这样做的原因是，有时希望使用某种特殊的动态内存分配方法。例如，可能有些分配子程序，他们的堆已耗尽，自动开始把一个磁盘文件当虚存储使用，或者用户希望控制某一片存储空间的分配等。
重载new和delete的格式如下：
#include <iostream>#include <stdlib.h>#include <string.h>using namespace std;class three_d{private: int x,y,z;public: three_d(int a,int b,int c); ~three_d() { cout << "Destructing\n"; } friend ostream & operator <<(ostream &stream,three_d obj);};three_d::three_d(int a,int b,int c){ cout << "Constructing\n"; x = a; y = b; z = c;}void *operator new(size_t size){ cout << "in threee_d new\n"; return malloc(size);}void operator delete(void *p){ cout << "in three_d delete\n" ; free(p);}ostream &operator <<(ostream &os,three_d obj){ os << obj.x << ","; os << obj.y << ","; os << obj.z << "\n"; return os;}int main(int argc,char *argv[]){ three_d *p = new three_d(1,2,3); three_d *p1 = new three_d(4,5,6); if(!p || !p1) { cout << "Allocation failure" << endl; return 1; } cout << *p << *p1; delete p; delete p1; int *pnum; pnum = new int; *pnum = 0; cout << "num = " << *pnum << endl; delete pnum; cout << "Application Run Successfully!" << endl; return 0;}