单项选择题

下面程序的执行结果是( )。 #include＜iostream＞ using namespace std; class building { public: building() {} building(unsigned stories, float breadths, float lengths) { story = stories; breadth = breadths; length = lengths;} void getstory(void) { cout＜＜"story is:"＜＜story＜＜endl;} void getarea(void) { area = length*breadth*story;cout＜＜"area is:"＜＜area＜＜endl;} private: unsigned story; float length; float breadth; float area; }; void main(void) { building b1,b2;building b3(10u,16.6,58.8); b1.getstory(); b1.getarea(); b2.getstory(); b2.getarea(); b3.getstory(); b3.getarea();}