填空题

下列程序的运行结果是 【11】 。
#include＜iostream, h＞
class Base

public:
void f(int x) cout＜＜"Base:"＜＜x＜＜end1;
;
class Derived: public Base

public:
void f(char * str) cout＜＜"Derived:"＜＜str＜＜end1;
;
void main(void)

Base * pd=new Base;
pd=new Derived;
pd-＞f(’a’)