（数码管静态显示）

<1>初始时刻8个发光二极管全部熄灭，8个数码管全部熄灭，蜂鸣器不发声。

<2>定义四个独立按键，当第一个按键按下时，蜂鸣器响一声，当按键松开时，八个数码管都显示“1”。当第二个按键按下时，蜂鸣器响一声，当按键松开时，八个数码管都显示“2”。当第三个按键按下时，蜂鸣器响一声，当按键松开时，八个数码管都显示“3”。当第四个按键按下时，蜂鸣器响一声，当按键松开时，八个数码管都显示“4”。

-(Static digital tube display)

<1> initial moment eight LEDs are off, eight digital tube all off, the buzzer does not sound.

<2> Define four separate buttons, when the first button is pressed, the buzzer sounds when the button is released, eight digital tube will display "1." When the second button is pressed, the buzzer sounds when the button is released, eight digital tube will display "2." When the third button is pressed, the buzzer sounds when the button is released, eight digital tube will display "3." When the fourth button is pressed, the buzzer sounds when the button is released, eight digital tube will display "4."