有以下程序 #include ＜iostream＞ using namespace std; class Base int a; public: Base(int x) a=x; void show() cout＜＜a; class Derived: public Base int b; public: Defived(int i):Base(i+ 1 ),b(i) void show() cout＜＜b; ; int main() Base b(5),*pb; Derived d(1); pb=&d; pb-＞show(); return 0;运行后的打印结果是______。