DinuR:
Anyone can fix my code for without serial monitor?
If you mean that you would like your PC keyboard to control an Arduino without any program running on the PC then that is not possible.
As @UKHeliBob has said you are not confined to using the Arduino Serial Monitor, but you will need some program running on the PC to detect the keypress and send a message to the Arduino - even if the message is only the character for the key that has been pressed.
...R