另一种mem_fun_ref

标准mem_fun_ref只能将数据交给类自己来处理，而不能由其它类来处理。下面这个mem_fun_ref可以将数据交给其它的类来处理.
  // TEMPLATE CLASS mem_fun_ref_t
template<class _Result,
 class _container,
 class _Ty>
 class mem_fun_ref_t
  : public std::binary_function<_container,_Ty, _Result>
 { // functor adapter (*left.*pfunc)(), non-const *pfunc
public:
 explicit mem_fun_ref_t(_container& c,_Result (_container::*_Pm)(_Ty&))
  : _Pmemfun(_Pm),_c(c)
  { // construct from pointer
  }

 _Result operator()(_Ty& _Param) //const
  { // call function
   return ((_c.*_Pmemfun)(_Param));
  }

private:
 _Result (_container::*_Pmemfun)(_Ty &); // the member function pointer
 _container& _c;
 };

template<class _Result,
 class _Container,
 class _Ty> inline
 mem_fun_ref_t<_Result, _Container,_Ty> mem_fun_ref(_Container& _c,_Result (_Container::*_Pm)(_Ty&))
 { // return a mem_fun_ref_t functor adapter
 return (mem_fun_ref_t<_Result,_Container, _Ty>(_c,_Pm));
 }

class Int
{
public:
 explicit Int(int i):m_i(i){}
 void print1()
 {}
private:
 int m_i;
};

class aaaa
{
public:
 aaaa(){};
 ~aaaa(){};

 void test(Int& i)
 {
 };
};
void ttt()
{
 aaaa bb;
 int a[]={1,2,3,4,5,6};
 std::vector<Int> va;

 va.push_back(Int(1));

 for_each(va.begin(),va.end(),mem_fun_ref<void,aaaa,Int>(bb,&aaaa::test));
}