[SOLVED] C++ problem

#include "stdafx.h"
#include <iostream>
#include <string>
#include <fstream>

using namespace std;

struct student {
	string firstName;
	string lastName;
	double GPA;
	int studentID;
};

int main()
{
	student s[10];

	ifstream in("people.txt");
	int numStudents = 0;

	const int size = 7;

	bool flag = true;
	for (int endIndex = size - 1; endIndex > 1 && flag; endIndex--) {
		flag = false;
		for (int startIndex = 0; startIndex < endIndex; startIndex++) {
			if (s[startIndex + 1].lastName < s[startIndex].lastName) {
				// adjacent elements in the array are out of order - swap them
				string temp = s[startIndex];
				s[startIndex] = s[startIndex + 1];
				s[startIndex + 1] = temp;
				flag = true; // set flag to show we have to continue...
				
			}
	}
	return 0;
}