#include <algorithm>
#include <iterator>
#include <vector>

#include "Student_info.h"
#include "grade.h"

using std::back_inserter;
using std::remove_copy_if;
using std::remove_if;
using std::vector;

vector<Student_info>
extract_fails(vector<Student_info>& students) {
	vector<Student_info> fail;
	remove_copy_if(students.begin(), students.end(),
	               back_inserter(fail), pgrade);
	students.erase(remove_if(students.begin(), students.end(),
	                         fgrade), students.end());
	return fail;
}