Package f2c

A Fortran 77 to C/C++ conversion program

http://netlib.org/f2c/

F2c converts Fortran 77 source code to C or C++ source files. If no
Fortran files are named on the command line, f2c can read Fortran from
standard input and write C to standard output.

General Commands (Section 1)
f2c
F2c converts Fortran 77 source code in files with names ending in `.f' or `.F' to C (or C++) source files in the current directory, with `.c' substituted for...