Program Call Subroutine

Within PROGRAM, how do I CALL a SUBROUTINE that's a new Fortran file in the same folder?

Thank you.

If you are using the Fortran 77 standard then you just make the CALL. You don't need any interface, the linker will sort out everything for you.

If you have Fortran 90 features then you will need an INTERFACE.

It's good now, thank you!