单项选择题
下面程序的运行结果是( )
#include class base{protected: int a;public: base(){ cout<<"0";}};class base1:virtual base{public: base1(){cout<<"1";}};class base2:virtual base{public: base2(){cout<<"2";}};class derived:public base1,public base2{public: derived(){cout<<"3";}};void main(){ derived obj; }
A、0123
B、3120
C、312
D、3012