source.h

51单片机C语言常用模块与综合系统设计实例精讲

extern char filter_1(void);
extern char filter_2(void);
extern char filter_3(void);
extern char filter_4(void);
extern char filter_5(void);
extern char filter_6(void);
extern char filter_7(void);
extern char filter_8(void);
extern char filter_9(void);
extern char filter_10(void);