这是一个用主板扬声器发声的代码，虽然这很普通，但代码中有一些乐理知识，可以给大家普及一下乐理知识，算一个趣味程序吧。-This is a motherboard speaker sound with the code, although this is very common, but the code has some knowledge of music, can tell you about popular music theory, considered it a fun program.