ITERATOR AND INDEX

#include <string>
#include<vector>
using namespace std;

struct  student_info //student information
{
 string name;
 double midsemester;
 double final;
 vector<double> homework; //school work
};

istream &read_hw(istream & in, vector<double> &hw)//read data
{
 double var_hw;
 
 if (in)
 {
  in.clear();
 }
 
 while (cin>>var_hw)
 {
  hw.push_back(var_hw);
 }
 
 in.clear();

 return in;
}