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: Derived(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______。