#include <cstdio>
#include <cstdlib>void * operator new(size_t unSize)
{printf("operator new called\n");return malloc(unSize);
}
void * operator new[](size_t unSize)
{printf("operator [] called\n");return malloc(unSize);
}void * operator new(size_t unSize, int nLine, const char * pFunc)
{printf("operator new called, line: %d, func: %s\n",nLine, pFunc);return malloc(unSize);
}
//注意：c++14才支持全局delete或delete【】有多个参数，参看参考资料2.下面两个delete不会覆盖全局的。
void operator delete(void * pMem,size_t unSize)
{printf("delete1: %u\n", unSize);free(pMem);
}
void operator delete[](void * pMem, size_t unSize)
{printf("delete[]: %u\n", unSize);free(pMem);}class A
{
public:A(int a = 0) :_a(a){   printf("constructor called\n");}  virtual ~A(){printf("~A()\n");}void * operator new(size_t unSize){printf(" calledA\n");return malloc(unSize);}
     //注意：但是支持自定义类型操作符new或delete重载支持size_t参数。即要删除对象的大小delete,要删除对象数组大小delete[].。void operator delete(void * pMem, size_t unSize){printf("delete2: %u\n", unSize);free(pMem);}void operator delete[](void * pMem, size_t unSize){printf("delete[]: %u\n", unSize);free(pMem);}private:int _a;
};class B: public A
{
public://隐式的为静态函数。void * operator new(size_t unSize, int nLine, const char * pFunc){printf("operator new called, line: %d, fileB: %s\n",nLine, pFunc);printf("operator new: %u\n", unSize);//_b=0;return malloc(unSize);}~B(){printf("~B()\n");}int _b;int _bb;
};int main()
{A * pA = new A(10);printf("#######\n");A * pB = new (__LINE__, __FILE__) B();printf("#######\n");A * szA = new A[10];B *szB = new B[10];printf("#######\n");delete pA; printf("#######\n");delete pB; printf("#######\n");delete [] szA;printf("#######\n");delete [] szB;printf("#######\n");
//下面两个不是自定义类，没有类重载new.delete故只能调用全局的，本程序全局不支持size_t参数，故只能调用标准C++中的全局operate delete.故不会打印信息。char * pC = new char[10];delete [] pC;
    char *pu = NULL;    delete pu;}

 calledA
constructor called
#######
operator new called,
operator new: 16
constructor called
#######
operator [] called
constructor called
constructor called
constructor called
constructor called
constructor called
constructor called
constructor called
constructor called
constructor called
constructor called
operator [] called
constructor called
constructor called
constructor called
constructor called
constructor called
constructor called
constructor called
constructor called
constructor called
constructor called
#######
~A()
delete2: 8
#######
~B()
~A()
delete2: 16
#######
~A()
~A()
~A()
~A()
~A()
~A()
~A()
~A()
~A()
~A()
delete[]: 84//注意84=4+8*10，数组分配的堆空间，第一个int空间放数组个数，接下来顺序放对象#######
~B()
~A()
~B()
~A()
~B()
~A()
~B()
~A()
~B()
~A()
~B()
~A()
~B()
~A()
~B()
~A()
~B()
~A()
~B()
~A()
delete[]: 164#######
operator [] called //调用覆盖的全局函数operate new [],打印信息。                    //delete[]调用全局的。