// This program creates a file friends.dot that can be read by Graphviz to
// see a graphical representation of a set of friendships.

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

public class FriendsData {
    public static void main(String[] args) throws FileNotFoundException {
        String[] names = {"Jessica", "Ashley", "Sarah", "Amanda", "Samantha",
                          "Emily", "Rachel", "Megan", "Michael", "Jacob",
                          "Tyler", "Joshua", "Christopher", "Andrew",
                          "Matthew", "Kyle"};

        PrintStream output = new PrintStream(new File("friends.dot"));
        output.println("graph {");
        Random r = new Random();
        Set<String> data = new TreeSet<String>();
        while (data.size() < names.length) {
            int i = r.nextInt(names.length);
            int j = r.nextInt(names.length);
            if (i < j)
                data.add("    " + names[i] + " -- " + names[j]);
            else if (i > j)
                data.add("    " + names[j] + " -- " + names[i]);
        }
        for (String s : data)
            output.println(s);
        output.println("}");
    }
}