Comment by theophrastus

I have a buddy at US Fish and Wildlife where they do river flow modeling with Fortran routines from the seventies formerly compiled on Windows machines. He was finding it increasingly difficult to get his all-powerful shadowy IT division to install a compliant MS Fortran compiler, and linux (somehow deemed governmentally untenable?) was out of the question. So i helped him get his ~2000 Fortran lines into C/C++. woowee... but did i see some hairy spaghetti code. A favorite maneuver was to jump out of a loop, change the loop counter on a subroutine branch, and jump back into the middle of the loop.