xchmp

import java.io.*;
import java.lang.Math.*;
 
public class NumberGame {
    private Console c;
    private int upperBound;
    private int lowerBound;
 
    public NumberGame() {
        c = System.console();
        if (c == null) {
            System.err.println("Unable to aquire console. Exiting...");
            System.exit(1);
        }
    }
 
    private void playGame() {
        c.format("Welcome to the guess-the-number game!%n");
        c.format("Think of a number between 1 and 100 and I'll try to " +
                 "guess it!%n");
        upperBound = 100;
        lowerBound = 1;
        boolean finished;
        do {
            finished = makeGuess();
        } while (finished == false);
        c.format("Thank you for playing!%n");
    }
 
    private boolean makeGuess() {
        if (upperBound == lowerBound) {
            makeAccusation(upperBound);
            return true;
        }
        else {
            int choice = ((upperBound - lowerBound) / 2) + lowerBound;
            if (Math.random() < 0.5) {
                boolean answer = askYesOrNo(String.format("%nIs your " +
                                   "number higher than %d? ", choice));
                if (answer) {
                    lowerBound = choice + 1;
                }
                else {
                    upperBound = choice;
                }
            }
            else {
                boolean answer = askYesOrNo(String.format("%nIs your " +
                                   "number lower than %d? ", choice));
                if (answer) {
                    upperBound = choice;
                }
                else {
                    lowerBound = choice - 1;
                }
            }
        }
        return false;
    }
 
    private boolean askYesOrNo(String query) {
        int answer = -1;
        String result;
        char resultChar = ' ';
        while (true) {
            result = c.readLine(query);
            if (result != "") {
                result = result.toLowerCase();
                if (result.length() > 0) {
                    resultChar = result.charAt(0);
                    if (resultChar == 'y') {
                        return true;
                    }
                    else if (resultChar == 'n') {
                        return false;
                    }
                }
            c.format("Please answer 'yes' or 'no'.%n");
            }
        }
    }
 
    private void makeAccusation(int accusation) {
        boolean result = askYesOrNo(String.format("%nIs your number %d? ",
                                                            accusation));
        if (result) {
            c.format("Awesome!%n");
        }
        else {
            c.format("One of us is obviously confused.%n");
        }
    }
 
    public static void main(String[] args) {
        NumberGame ng = new NumberGame();
        ng.playGame();
    }
}