ctest : ctest.o complex.o gcc ctest.o complex.o -g -o ctestThis dependency rule tells make that ctest (the target) depends on the two files ctext.o and complex.o. If ctest doesn't exist, or if it is older than either ctest.o or complex.o, then it can be brought up to date by executing the gcc command.
ctest : ctest.o complex.o
gcc ctest.o complex.o -g -o ctest
ctest.o : ctest.c complex.h
gcc ctest.c -c -g
complex.o : complex.c complex.h
gcc complex.c -c -g