预加氢催化剂预硫化的注意事项有哪些？

下列程序的输出结果是______。 #include＜iostream＞ using namespace std; class base { public: int n; base(int x){n=x;} virtual void set(int m){n=m;cout＜＜n＜＜’’;} }; class deriveA:public base { public: deriveA(int x):base(x){} void set(int m){n+=m;cout＜＜n＜＜’’;} }; class deriveB:public base { public: deriveB(int x):base(x){} void set(int m){n+=m;cout＜＜n＜＜’’;} }; int main( ) { deriveA d1(1); deriveB.d2(3); base*pbase; pbase=&d1; pbase-＞set(1); pbase=&d2; pbase-＞set(2); return 0; }