структуры, нужно подправить код

#include "stdafx.h"
#include "conio.h"
 
struct student
{ 
char surname[20];
int estimate1;
}
gruppa [30];
 
void main (void)
{ int i,j,k, priznak=1;
printf ("List of 30 students\n");
 
for (i=1;i<=30;i++)
{ 
printf ("Enter data of student %d or 0 for exit\n",i);
printf ( "surname:");
fflush(stdin);
gets (gruppa [i].surname);
printf ("enter one mark!");
fflush(stdin);
scanf ("%d", &gruppa[i]. estimate1);
k=i;
printf ("enter 1-for continue 0-for end");
scanf ("%d",&priznak);
if (!priznak) break;
}
for (i=0;i<25;i++)
{ 
printf ("enter number of student?\n");
scanf ("%d",&j);
if (j>k)
{ 
printf ("\nNo data!");
continue;
}
printf ("Student:%s\n", gruppa[j].surname);
printf ("mark: %d\n", gruppa[j].estimate1);
printf ("enter data of student or 0 for exit?\n");
scanf("%d", &priznak);
if (!priznak) break;
}
 
gets ("programme end!Press any key...");
getch ();
}

#include "stdafx.h"
#include <iostream>
#include <string>
#include <vector>
#include <iterator>
#include <numeric>
 
class Record
{
public:
Record() : av(0.0f) {}
 
friend std::istream &operator >> (std::istream &stream, Record &rec); 
friend std::ostream &operator << (std::ostream &stream, const Record &rec); 
 
float getAv() const {return av;}
private: 
std::string surname;
float av;
};
 
struct sum : public std::binary_function<float, Record, float> 
{
float operator()(float a, Record b) {return a + b.getAv();}
};
 
struct lesser : public std::binary_function<Record, float, bool> 
{
bool operator()(Record b, float a) const {return b.getAv() < a;}
};
 
std::istream &operator >> (std::istream &stream, Record &rec)
{
std::cout << "Surname: ";
stream >> rec.surname;
std::cout << "Score: ";
stream >> rec.av;
return stream;
}
 
std::ostream &operator << (std::ostream &stream, const Record &rec)
{
stream << rec.surname << " " << rec.av;
}
 
int main()
{
std::vector<Record> records;
std::cout << "Enter data. Send eof (Ctrl+Z) to terminate input\n";
std::copy(std::istream_iterator<Record>(std::cin), std::istream_iterator<Record>(), std::back_inserter(records));
 
std::cout << "All students: \n";
std::copy(records.begin(), records.end(), std::ostream_iterator<Record>(std::cout, "\n"));
 
float avscore = std::accumulate(records.begin(), records.end(), 0.0f, sum()) / records.size();
std::cout << "Average score: " << avscore << std::endl;
 
std::cout << "List of student with great results\n"; 
std::remove_copy_if(records.begin(), records.end(), std::ostream_iterator<Record>(std::cout, "\n"), std::bind2nd(lesser(), avscore));
}

std::remove_copy_if(records.begin(), records.end(), std::ostream_iterator<Record>(std::cout, "\n"), std::bind2nd(lesser(), avscore));