填空题
有如下程序: #include<iostream> using namespace std; class Base public; int m,n; ; class Derived1:______Base; class Derived2:public Derivedl public: void SetMN(int M,int N)m=M;n=N; int GetSumMN()return(m+n); ; int main() Derived2 objD; objD.SetMN(3,4); cout<<"M+N="<<objD.m+bojD.n<<endl; return 0: