key.c(2): warning C318: can‘t open file ‘Delay.h‘key.c(17): warning C206: ‘Delay‘: missing function

 key.c(2): warning C318: can't open file 'Delay.h'
key.c(17): warning C206: 'Delay': missing function-prototype
key.c(17): error C267: 'Delay': requires ANSI-style prototype

解决方案：在该目录下添加以上没有的.c和.h文件。