下面程序的执行结果为 ‘ #include"iostream" using namespace std; class A int a; public: void Sera(int x)a=x; void Display_a()cout<<a<<endl; ; class B int b; public: void Setb(int x) b=x; void Dispaly_b() cout<<b<<endl; ; class C:public A,private B private: int c; public: void Setc(int x,int y,int z) c=z;Sera(x);Serb(y); void Display_c()cout<<c<<endl; ; ① void main() ② ③ C cc; ④ cc.Seta(1); ⑤ cc.Display_a(); ⑥ cc.Setc(2,2,3); ⑦ cc.Dispaly_b(); ⑧ cc.Display_c();