程序代码：

#include <iostream>
using namespace std;
class Ex
{
public:
    Ex()
    {
        cout<<"Ex::Ex()"<<endl;
    }

    Ex(const Ex&) 
    {
        cout<<"Ex::Ex(const Ex&)"<<endl;
    }

    Ex& operator=(const Ex& e)
    {
        cout<<"Ex::operator="<<endl;
        return *this;
    }

    ~Ex()
    {
        cout<<"Ex::~Ex"<<endl;
    }

    virtual void pisz()
    {
        cout<<"Ex::pisz()"<<endl;
    }
};

class Ex2:public Ex 
{
public:
    Ex2() 
    {
        cout<<"Ex2::Ex2()"<<endl;
    }

    Ex2(const Ex2&) 
    {
        cout<<"Ex2::Ex2(const Ex2&)"<<endl;
    }

    Ex2& operator=(const Ex2& e)
    {
        cout<<"Ex2::operator="<<endl;
        return *this;
    }
    
    ~Ex2()
    {
        cout<<"Ex2::~Ex2"<<endl;
    }

    void pisz()
    {
        cout<<"Ex2::pisz()"<<endl;
    }
};

class A
{
    int a;

public:
    A(int r):a(r)
    {
        cout<<"A::A(int)"<<endl;
    }

    A(const A& r):a(r.a) 
    {
        cout<<"A::A(const A&)"<<endl;
    }

    A& operator=(const A& r)
    {
        a=r.a;
        cout<<"A::operator="<<endl;
        return *this;
    }

    ~A()
    {
        cout<<"A::~A"<<endl;
    }

    int get()const
    {
        return a;
    }
};

void fun2(A& a)
{
    cout<<"fun2"<<endl;
    if(a.get()<0)
    throw Ex();
    if(a.get()==0)
    throw Ex2();
}

void fun(A a)
{
    cout<<"fun"<<endl;
    try
    {
        fun2(a);
    }
    catch(Ex e)
    {
        e.pisz();
        throw e;
    }
}

int main()
{
    A a(0);
    try
    {
        fun(a);
    }
    catch(Ex e)
    {
        e.pisz();
    }
    return 0;
}