/tmp/ccHsBaRA.o: In function `dayofMonth':
hotel-db.c:(.text+0x0): multiple definition of `dayofMonth'
/tmp/cch4hiuu.o:hotel-main.c:(.text+0x0): first defined here
/usr/lib/gcc/x86_64-linux-gnu/6/../../../x86_64-linux-gnu/Scrt1.o: In function `_start':
(.text+0x20): undefined reference to `main'
collect2: error: ld returned 1 exit status