/usr/bin/ld: /tmp/ccSyOf9s.o: in function `Assist(unsigned char*, int, int, int)':
advisor.cpp:(.text+0x2a1): undefined reference to `GetRequest()'
/usr/bin/ld: advisor.cpp:(.text+0x2dc): undefined reference to `PutBack(int)'
/usr/bin/ld: /tmp/ccQdrT7s.o: in function `main':
advisor_grader.cpp:(.text.startup+0xe6): undefined reference to `ComputeAdvice(int*, int, int, int)'
collect2: error: ld returned 1 exit status
/usr/bin/ld: /tmp/ccZ8tiXe.o: in function `main':
assistant_grader.cpp:(.text.startup+0x21e): undefined reference to `Assist(unsigned char*, int, int, int)'
collect2: error: ld returned 1 exit status