add else statement

  private void turn(int i) {
    if (this.swiches[i] == 0) {
      this.swiches[i] = 1;
    }
    else {
      this.swiches[i] = 0;
    }
    if (this.lamp == 0) {
      this.lamp = 1;
    }
    else {
      this.lamp = 0;
    }
  }