/usr/bin/ld: /tmp/ccXHA97j.o: in function `main':
grader.c:(.text.startup+0x6b): undefined reference to `init'
/usr/bin/ld: grader.c:(.text.startup+0xd0): undefined reference to `calculate'
/usr/bin/ld: grader.c:(.text.startup+0x13e): undefined reference to `update'
collect2: error: ld returned 1 exit status