gistfile1.m

- (void)updateCorrectKeysPressed {
    correctKeysPressed_++;
    correctKeysPressedThisGame_++;
    // update the current score, 10 points for a correct key and 3 points for each consecutive correct key
    score_ += 10 + (correctKeysPressedThisGame_ - 1) * 3;
    
    
    if (correctKeysPressed_ && correctKeysPressed_ % 10 == 0) {
        // compute the bonus based on consecutive correct keys
        NSInteger bonus = score_ * ((float)correctKeysPressed_/200);
        score_ += bonus;
        NSString *achievement = [NSString stringWithFormat:@"%d keys in a row! (+%d)", correctKeysPressed_, bonus];

        // show the achievement notification
        [self achievementUnlocked:achievement];
    }

    [scoreLabel_ setString:[NSString stringWithFormat:@"Score: %d", score_]];
}