有如下程序： #include＜iostream＞ using namespac

问题：

有如下程序：
#include＜iostream＞
using namespace std;
class ONE

public:
virtual void f() cout ＜＜ "1";
;
class TWO: public ONE

public:
TWO() cout ＜＜ "2";
;
class THREE: public TWO

public:
virtual void f() TWO::f(); cout ＜＜ "3";
;
int main()

ONE aa, *p;
TWO bb;
THREE cc;
p = &cc;
P-＞f();
return 0;

执行上面程序的输出是______