AARONs-MBP:Downloads Aaron$ gcc -o proj4 project4_2.c

Undefined symbols for architecture x86_64:
  "_dlsode_", referenced from:
      _main in project4_2-6473ff.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

AARONs-MBP:Downloads Aaron$ gfortran -o proj4 project4_2.c

    Undefined symbols for architecture x86_64:
      "_dlsode_", referenced from:
          _main in cccuKljb.o
    ld: symbol(s) not found for architecture x86_64
    collect2: error: ld returned 1 exit status