Fortran-77 is a very old code, who lives in 32-bit computer.
In Ubuntu-16, the compiler g++, gcc, or gfortran are “basically the same” (as far as I understand, correct me if I am wrong.) that they only support fortran-95.
In order to compile Fortran-77 code, I tried many way, but the only way is install g77 from external source, and add -m32 for the compiling flag.
The g77 compiler can be downloaded in here (I download from the web, If I violated some copy right, please let me know):
or, people can search in google by
people need to extract, change the mod of install.sh to be executable.
tar -xzvf g77_x64_debian_and_ubuntu.tar.gz cd g77_x64_debian_and_ubuntu chmod +x ./install.sh ./install.sh
Hope it help. :)