int main() { ifstream inFile("file.in",ios::in); ofstream outFile("file.out",ios::out); float m,h; Data data; if(!inFile||!outFile){ cerr<<"Failed Opening"<<endl; } else { while(inFile>>m>>h){ data.Get_Mass(m); data.Get_height(h); outFile<<data.Cal_BMI()<<" "<<data.Set_cate()<<endl; } } return 0; }