若有以下程序： #include ＜iostream＞ using namespace std; class data public: int x; data(int x) { data: :x=x; }; class A private: data d1; public: A(int x): d1(x){} void dispa() { cout＜＜d1.x＜＜","; } }; class B: public A { private: data d2; public: B(int x): A(x-1),d2(x){} void dispb() { cout＜＜d2.x＜＜end1; } }; class C: public B { public: C(int x): B(x-1){} void disp() { dispa(); dispb(); } }; int main() { C obj(5); obj.disp(); return 0; 程序执行后的输出结果是 }