#include<iostream.h>
class A
{
public:
      A()   
      {
            cout<<"调用构造函数"<<endl; 
     }
      A(const A& a)
      {
            cout<<"调用拷贝构造函数"<<endl;
      }
      ~A()
      {
            cout<<"调用析构函数"<<endl;
      }     
};
A fun1(A a);
A &fun2(A &a);		
int main()
{
      A a;                          //声明对象
      cout<<"传值调用"<<endl;
      fun1(a);
      cout<<"引用调用"<<endl;
      fun2(a);
      return 0;
}
A fun1(A a)
{
      cout<<"返回对象"<<endl;
      return a;
}
A &fun2(A &a)
{
      cout<<"返回引用"<<endl;
      return a;
}