you should use "indexer" as the file name of your executable of project 1, otherwise the grading script will fail to test your programs. To name your executable correctly, your Makefile should look like:

CC = ...
CFLAGS = ...

...

# Here use "indexer" as the name of executable
indexer: indexer.cpp ...
	$(CC) $(CFLAGS) $? $(LDFLAGS) -o $@

clean:
	-rm *.o *~ core