若有以下程序： #include ＜iostream＞ using namespace std; class Base { private: int a,b; public: Base(int x, int y) { a=x; b=y; } void disp () { cout＜＜a＜＜" "＜＜b＜＜end1; } }; class Derived : public Base { private: int c; int d; public: Derived(int x,int y, int z,int m) :Base(x,y) { c=z; d=m; } void disp () { cout＜＜c＜＜" "＜＜d＜＜end1; } }; int main() { Base b(5,5),*pb; Derived obj(1,2,3,4); pb=&obj; pb-＞disp(); return 0; } 执行程序后的输出结果是( )。