import java.util.Scanner;

public class WordSeq {
    final int INIT_SZ = 5;   // the initial array size
    String[] sequence;       // where we store values
    int next;                // next available index

    /**
     * Allocates an initial array.
     */
    public WordSeq() {
	sequence = new String[INIT_SZ];
	next = 0;
    }

    /**
     * Appends a word to the WordSeq.
     * @param word The word.
     */
    public void append(String word) {
	if (next == sequence.length) {
	    expand();
	}
	sequence[next] = word;
	next++;	
    }

    /**
     * Returns a string representing the entire sequence.
     * @return Stringified sequence.
     */
    public String toString() {
	String s = "";
	for (int i = 0; i < next; i++) {
	    s += sequence[i] + " ";
	}
	return s;
    }

    /** 
     * Doubles storage, copies elements, and
     * replaces the original array.
     */
    private void expand() {
	// Uncomment this line if you want to see when we expand:
	// System.out.println("DEBUG: expanding!");
	String[] sequence2 = new String[sequence.length * 2];
	for (int i = 0; i < sequence.length; i++) {
	    sequence2[i] = sequence[i];
	}
	sequence = sequence2;
    }

    /**
     * Prompts the user to enter a word.  If the entered word is not 'exit',
     * then it stores the word in the given WordSeq and returns true.
     * Otherwise, it returns false.
     * @param s A scanner to read input
     * @param ws The sequence with which to append
     * @return False iff the user wants to quit.
     */
    public static boolean promptUser(Scanner s, WordSeq ws) {
	System.out.print("Enter a word (or 'exit' to quit): ");
	String word = s.next();
	if (word.equals("exit")) {
	    return false;
	} else {
	    ws.append(word);
	    return true;
	}
    }
    
    /**
     * Ask the user for a bunch of words.  When the user
     * types 'exit', print the sequence and quit.
     * @param args command-line arguments, ignored
     */
    public static void main(String[] args) {
	Scanner s = new Scanner(System.in);
	WordSeq ws = new WordSeq();	
	while (promptUser(s, ws)) {}
	System.out.println(ws);
    }
}