while(flag)
  

  {
  

  flag=0;
  

  cout<<"必修课程“"<<(*student)[i].getName()<<"”的成绩(0-100)：";
  

  cin>>mark;
  

  while(cin.fail())
  

  {
  

  

  //cout<<cin.fail()<<endl;
  

  cin>>mark;
  

  }
  

  try{dynamic_cast<ObligatoryCourse &>((*student)[i]).setMark(mark);}
  

  catch(ExceptionCourse a)
  

  {
  

  cout<<"\n"<<a.what();
  

  a.print();
  

  cout<<"\n";
  

  flag=1;
  

  }
  

  }
 

  bool ObligatoryCourse::setMark(int m)
  

  {
  

  if ((m<=100)&&(m>=0)) {
  

  mark=m;
  

  return true;
  

  }else{
  

  ExceptionCourse a;
  

  throw a;
  

  //return false;
  

  

  }
  

  }