grader-lite: main.o
  g++ -o grader-lite main.o gradedThings.o grades.o students.o

main.o: gradedThings.h grades.h students.h
  g++ -c main.C
gradedThings.o: gradedThings.h
  g++ -c gradedThings.C
grades.o: grades.h
  g++ -c grades.C
students.o: students.h
  g++ -c students.C