The Trip/Celfin

~cpp
#include <iostream>
#include <cmath>
using namespace std;

#define MAX_STU 1000

double student[MAX_STU+1];
int student_num, i, j, sum, average;
double least, most;

double calculate()
{
	sum = 0;
	least = most = 0.0;
	for(j=1; j<student_num+1; j++)
	{
		student[j] = student[j]*100;
		sum = sum + student[j];
	}
	average = sum/student_num;
	for(j=1; j<student_num+1; j++)
	{
		if(student[j]<average)
			least = least + average - student[j];
		if(student[j]>average+1)
			most = most + student[j] - average - 1;
	}
	if(most <least )
		return least;
	return most;
}

int main()
{
	cout.setf(ios::fixed, ios::floatfield);
	cout.setf(ios::showpoint);
	cout.precision(2);
	
	while(cin>>student_num)
	{
		if(student_num==0)
			break;
		for(i=1; i<student_num+1; i++)
			cin >> student[i];
		cout << "$" << calculate()/100 <<endl;
	}
	return 0;
}