f2c and p2c are useful if you have some code written in FORTRAN or Pascal that you want to rewrite in C. The C code produced by these two programs can usually be compiled directly by GCC without modification.
If you are converting a small FORTRAN or Pascal program, you can use f2c or p2c without any options. If the program you want to convert is large and contains a lot of files you may need to use some command line options.
To use f2c on a FORTRAN program, enter the following command:
f2c my_fortranprog.f
Note: f2c requires that the program to be converted has an extension of .f or a .F .
To convert a Pascal program into a C program, enter the following command:
p2c my_pascalprogram.pas
The C source code produced by both programs has the same filename as the original, but with a .c extension instead of .f or .pas.
The file name is the same as the original, but with a .c extension.