Fortran 90 for the Fortran 77 Programmer

Version 2.3

This tutorial is written in order to ease the transition from the very common and popular programming language Fortran 77 to the more modern Fortran 90. This transition uses the fact that Fortran 77 is a pure subset of Fortran 90.

This HTML version can be used from both UNIX and Windows. It is recommended that the reader has the following features implemented in such a way that the following four fonts are easily distinguished: Bold font, Italic font, Courier or TTY font, and normal font. The Courier font is being used for all Fortran words and all code.

Users of Netscape and Mosaic (2.0 on Windows or 2.7b3 on UNIX) can now enjoy a light green background. Netscape Version 2.0 seems to be very sensitive to minor errors in the HTML-code. I have now tried to compensate for this. Please report any remaining errors!

This hypertext version is available on the net as http://www.nsc.liu.se/~boein/f77to90/f77to90.html. It can also be downloaded.

When reading a chapter (or appendix) the arrows at the bottom will bring you to the previous chapter, the tutorial home page (this page, at the start of the contents) or the next chapter.

Permission is granted to copy and/or print this hypertext as long as the copyright notice and this permission is included on all copies.

This material is also available (with some exceptions) as one book in Russian and a manuscript in Chinese.

A complete textbook in Swedish on Fortran 90 has been prepared, and is available both electronically in a PostScript version and in a hypertext version, and in printed form.

Further information on Fortran 90 is available via Bo Einarsson's Fortran page.

Views, suggestions and corrections are most welcome for the next edition of this tutorial. The HTML version will be continuously updated.

Linköping and Novosibirsk, August 1993
Bo Einarsson and Yurij Shokin

• Technical information
• Preface
• Introduction
• Chapters
  • 1. Notables in the transition from Fortran 77 to Fortran 90
  • 2. Specifications
  • 3. The layout of a program (free form and fix form)
  • 4. Format
  • 5. The same source code for Fortran 77 and Fortran 90 ?
  • 6. Control statements
  • 7. Program units
  • 8. Keyword arguments and default arguments
  • 9. Recursion
  • 10. Generic routines
  • 11. The use of arrays and array sections
  • 12. Pointers
  • 13. The new precision concept
  • 14. Additional problems at the transition
  • 15. Use of program libraries
  • 16. Peculiarities in the language Fortran 90
  • 17. Status of Fortran 95
  • 18. Different Fortran standards
• Answers and comments to the user exercises
• References
• Appendices
  • App. 1. Fortran and Pascal
  • App. 2. Summary of Fortran 77 statements
  • App. 3. Summary of the new features in Fortran 90
  • App. 4. Backward and Forward compatibility
  • App. 5. Intrinsic functions and subroutines in Fortran 90
  • App. 6. Fortran 90/95 systems
    • Apogee
    • Absoft
    • Cray
    • Digital
    • Fujitsu
    • IBM
    • Lahey
    • NAG
    • NASoftware
    • NDP
    • Pacific-Sierra
    • Portland Group
    • SGI
    • SunSoft
  • App. 7. The historical development of Fortran
  • App. 8. High Performance Fortran
  • App. 9. Explanation of certain terms
  • App. 10. Argument association
  • App. 11. Computer Exercises
  • App. 12. Editors
  • App. 13. Computer Environments
• Marketing information
  • The Tutorial
  • Bo Einarsson
  • Yurij Shokin