计频器有两种测量方法，即测频和测周，我们提出选用测频的方法，但是有时老师也会让我们编写可以选用测频、测周并且两者可以自动选择的程序，本程序即可达到这个要求。-Frequency meter, there are two measuring methods, that is, the frequency measurement and test week, we put forward to use frequency measure,