题目:用按键或者按键矩阵输入任意4位数(不为0),并在数码管上做显示以输入2761为例,数码管显示:2761-276.1-27.61-2.761-7612-761.2-76.123-7.612-7127-612.7-61.27-6.127-1276-127.6-12.76-1.276-2761要求