Re: Loops (was Re: do { quit; } else { })

Janis Papanagnou <janis_papanagnou+ng@hotmail.com> writes:

(While there's some "C" stuff in here it contains a lot of non-"C"
samples for comparison. So [OT]-sensible folks may want to skip this
post.)
On 14.04.2025 12:16, bart wrote:

[...]

Fortran's loops looked like this:
 
    do 100 i = a, b
        s1
        s2
        ...
100 continue

>
Okay, I see what you want; just two values (from, to).
>
This Fortran stuff looks really sick (for my taste)! - The "do 100"
sounds like iterating 100 times, line numbers, 'continue' keyword,
and a list a,b meaning iteration over a range. - Can it be worse?
(Later Fortran versions allow a slightly better syntax, but it's
basically the same anachronistic crude syntax.)

To any programmer familiar with that version of Fortran, the 100 doesn't
look like iterating 100 times.  It looks like a label, and it's
reasonably consistent with other constructs that refer to labels.  The
syntax isn't great, but don't judge an unfamiliar language syntax by one
example.

In _minimalistic_ languages I'd prefer, for example, a style like
in Pascal (or in similar languages)
>
  for i := a to b do
     statement_block;
>
It's simple, and a clean formalism.
>

 
The C equivalant is this:
 
    for (i = a; i <= b; ++i)
        stmt
 
Differences:
 
* Fortran has an official loop index variable 'i'.

>
You are saying that you could not use 'j' ? (This is certainly
different from my memories.) - Anyway, having dedicated variables
for integer types is sick in itself, also if used without loop.

No, he's saying that in the example Fortran loop "do 100 i = a, b", the
variable i is the index variable for that loop.  It could be any
variable name.  (Fortran defaults variables with names starting with
i..n to integer; "implicit none" overrides that and requires everything
to be declared.  I'm not certain whether modern Fortran still does that.)

[...]

--
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
void Void(void) { Void(); } /* The recursive call of the void */