编写并实现LED排灯(D2~D10)显示程序，实现按键与LED的关联，即4个按键S3~S6控制4个LED灯，按键按下相应的灯亮，松开相应的灯灭。-Prepare and implement LED bar lights (D2 ~ D10) display program, to achieve the association with the LED buttons that four key S3 ~ S6 control four LED lights, press the corresp