Fortran is 21 years old; many would say that it has not reached adulthood but senility. Yet it remains the language of use in the overwhelming majority of scientific applications of computers and no end to this situation is in sight. Moreover, its evolution through the standards process is very slow, too slow to give any hope that Fortran will ever in this way become a language in which structured programs can be easily and effectively written.

A technique for structuring FORTRAN programs is reviewed, and a preprocessor is described which converts pure structured code into standard FORTRAN. It is claimed that structured FORTRAN is generally easier to read and write than unstructured FORTRAN. Actual examples are given of structured FORTRAN and results of preprocessing.