https://github.com/ckormanyos/hello_f77

The epic Hello World program in the Fortran77 language
https://github.com/ckormanyos/hello_f77

fortran fortran77 hello-world

Last synced: 24 days ago
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The epic Hello World program in the Fortran77 language

• Host: GitHub
• URL: https://github.com/ckormanyos/hello_f77
• Owner: ckormanyos
• License: bsl-1.0
• Created: 2023-08-05T07:15:56.000Z (over 1 year ago)
• Default Branch: main
• Last Pushed: 2023-12-21T05:30:59.000Z (11 months ago)
• Last Synced: 2024-04-28T03:19:38.239Z (6 months ago)
• Topics: fortran, fortran77, hello-world
• Language: Fortran
• Homepage:
• Size: 154 KB
• Stars: 1
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
hello_f77

==================



    

        

    

        

    

        



hello_f77 implements the epic _Hello_ _World_ program in `FORTRAN77`.

## Compile on `*nix`

Use GCC to compile [`hello_f77.f`](./hello_f77.f). This requires the presence

of `fortran` in the enabled languages of the GCC build (see image and description below).

The `libgfortran` library must also be installed on the system for proper linking.

```sh

cd hello_f77

g++ hello_f77.f -x f77 -std=legacy -O2 -lgfortran -o hello_f77.exe

```

### Query if `fortran` Is Available

If you are unsure if `fortran` is available, query GCC for the presence of `fortran`.

Use the command shown below and search for `fortran` in the list of GCC's

_enabled_ languages.

```sh

g++ -v

```

![](./images/gcc_has_fortran.jpg)

## Source Listing

The complete source is provided below.

It can be found in [`hello_f77.f`](./hello_f77.f).

You can even try this program at the following

[short link](https://godbolt.org/z/sMoP43Mcc) to [godbolt](https://godbolt.org).

```fortran

CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC

C

C     Copyright Christopher Kormanyos 1985 - 2023.

C     Distributed under the Boost Software License,

C     Version 1.0. (See accompanying file LICENSE_1_0.txt

C     or copy at http://www.boost.org/LICENSE_1_0.txt)

C

C     g++ hello_f77.f -x f77 -std=legacy -O2 -lgfortran -o hello_f77.exe

C     See also https://godbolt.org/z/sMoP43Mcc

      PROGRAM HELLO

      IMPLICIT NONE

      CHARACTER*32 MY_TEXT

      MY_TEXT = 'Hello World'

      WRITE (*,*) MY_TEXT

      END

```

## Historical Perspective

`FORTRAN` (in particular `FORTRAN77` or `f77`) was there early in the game.

From a subjective standpoint, however, it seemed like there was an intermediate

time epoch during which its support was lost, missing, or in some other

way incomplete and obscure.

Now trusty old `f77` is back. It is properly supported as part of GCC on many systems.

There is also (as there should be) conformance with legacy code.

This includes support for the $128$-bit floating-point data type `REAL*16`.

Even though `REAL*16` (and its complex counterpart `COMPLEX*32`)

are not used in _Hello_ _World_, they are available for number crunching

when needed. These high-precision types can be difficult to find in the world of

high-performance, efficient, object-code-generating programming languages.

_Even_ _today_ this makes `FORTRAN77` still a leading program

for high-performance, high-precision numerical calculations.