//
// Example of 
// - class with methods
// - using arrays
// - command line argument
// - reading a file
// - new for statement (see mean)
// - Array.sort
// - statistics
//

import java.io.*;
import java.util.*;

/** A data set of integers read from file, using ArrayList<Integer>
    @author Patrick Prosser
    @ version 1.0 */

public class DataSet {

    private ArrayList<Integer> data;
    private int n;

    /** create a data set from file, where file is an unknown number of numbers
	@param fname is the name of the file */

    public DataSet(String fname) throws IOException {
	data = new ArrayList<Integer>();
	n = 0;
	Scanner sc = new Scanner(new File(fname));
	while (sc.hasNext()){data.add(sc.nextInt());n++;}
    }

    public int size(){return data.size();}

    public String toString(){
	String s = "";
	for (int x : data) s = s + x + " ";
	return s;
    }

    public int mean(){
	int sum = 0;
	for (int x : data) sum = sum + x;
	return sum/n;
    }

    public int min(){
	int min = data.get(0);
	for (int x : data) min = Math.min(min,x);
	return min;
    }
    
    /** maximum in the data set */
    public int max(){
	int max = data.get(0);
	for (int x : data) max = Math.max(max,x);
	return max;
    }

    /** standard deviation */
    public double stDev(){
	int mean, sum, diff;
	mean = mean(); sum = diff = 0;
	for (int x : data){diff = x - mean; sum = sum + diff*diff;}
	return Math.sqrt((double)sum/(double)n);
    }

    /** gets file name from command line */
    public static void main(String[] args) throws IOException {

	DataSet x = new DataSet(args[0]);
	System.out.println("n: "+ x.size() +" mean: "+ x.mean() +" min: "+ x.min() 
			   +" max: "+ x.max() +" stDev: "+ x.stDev());
	//System.out.println(x);
    }
}