程序代码：

#include <cstddef>
#include <iostream>
#include <conio.h>
using namespace std;
template<class T,int sz=1>class PWrap{
T*ptr;
public:
       class Rangeerror{};
       PWrap(){
        ptr=new T[sz];
        cout<<"PWrap constructor"<<endl;}
        ~PWrap()
        {delete[]ptr;
        cout<<"PWrap destructor"<<endl;}
       T& operator [](int i)throw(Rangeerror){
                   if(i>=0&&i<sz)return ptr[i];
        throw Rangeerror();}
        };
class Cat{
public:
       Cat(){cout<<"Cat()"<<endl;}
       ~Cat(){cout<<"~Cat{}"<<endl;}
       void g(){}};
class Dog{
public:
       void* operator new[](size_t){
             cout<<"Allocating a Dog"<<endl; //这个重载在哪里用到了？size_t是无符号长整型吗？ （1）
             throw 47;}
       void operator delete[](void* p){
            cout<<"Deallocating a Dog"<<endl;
            ::operator delete[](p);}   //这一句能不能换种写法？它的意思是不是清除p的空间，是不是还原运算符重载？
            };
class UseResources{
      PWrap<Cat,3>cats;
      PWrap<Dog>dog;
      public:
      UseResources(){cout<<"Use()"<<endl;}
      ~UseResources(){cout<<"~Use()"<<endl;}
      void f(){cats[1].g();}};//是这里用了 （1）重载？
int main()
{
try{UseResources ur;}catch(int){
  cout<<"inside handler"<<endl;}catch(...){
                cout<<"inside catch(...)"<<endl;}
                getch();
}