填空题

有如下程序：#include <iostream> using namespace std; class Base{ public: Base(int x=0):valB(x){ cout<<valB; } ~Base(){ cout<<valB; } private: int valB; }; class Derived:public Base{ public: Derived(int x=0,int y=0):Base(x),valD(y){cout<<valD;} ~Derived(){cout<<valD;} private: int valD; }; int main(){ Derived objl2(2,3); return 0; } 运行时的输出结果是（）。