基于单片机1602和矩阵键盘的密码锁

Build target 'Target 1'
compiling main.c...
main.c(4): warning C318: can't open file 'compact.h'
main.c(5): warning C318: can't open file 'lcd1602.h'
main.c(6): warning C318: can't open file 'iic.h'
main.c(7): warning C318: can't open file 'keyboard.h'
main.c(8): warning C318: can't open file 'sounder.h'
MAIN.C(26): error C202: 'beep': undefined identifier
Target not created
楼主  为什么程序运行后是这样的   求解答   谢谢