Which Fortran standard?

Fortran 2018 with GFortran. Older standards (77, 90, 95, 2003, 2008) all compile.

GFortran's coarray support is single-image by default; distributed multi-image requires OpenCoarrays (not in the sandbox).

Fortran · online compiler

Run Fortran online

Run Fortran online — GFortran, Fortran 2018 standard, browser-hosted.

Version

Fortran 2018

Firecracker microVM live per-test verdicts multi-file compile

Fortran is not dead — it is the workhorse of scientific computing and every serious HPC system runs kilotons of it. Modern Fortran (2003 → 2018) has object-orientation, coarrays for parallelism, and C interop.

ls-judge compiles Fortran 2018 with GFortran inside a Firecracker microVM. Multi-file projects work.

Starter code

What you get in Fortran

Clicking "Run now" opens the playground with this exact code and a matching test case pre-loaded — passes on first Run.

fortran

Fortran 2018

program solution
  implicit none
  integer :: n
  read(*,*) n
  write(*,'(i0)') n * 2
end program solution

stdin →

expected →

FAQ

Common questions about Fortran on ls-judge

Which Fortran standard?: Fortran 2018 with GFortran. Older standards (77, 90, 95, 2003, 2008) all compile.
Coarrays?: GFortran's coarray support is single-image by default; distributed multi-image requires OpenCoarrays (not in the sandbox).
BLAS / LAPACK?: Not pre-installed.
Free?: Yes.