Early Fortran already had loops, but with labels:

         INTEGER A(4,4), C, R 
         ... 
         DO 10 WHILE ( C .NE. R ) 
                A(C,R) = A(C,R) + 1 
         C = C+1 
  10     CONTINUE

Note that Fortran has evolved significantly over time. This is how you would write the same in Fortran 77:

       INTEGER A(4,4), C, R 
       ... 
       C = 4 
       R = 1 
       DO WHILE ( C .GT. R ) 
              A(C,R) = 1 
              C = C - 1 
       END DO

Those are just regular loops, though, right? I’m looking for the posttest loop, sometimes known as the do…while or until loop. There seems to be a unfortunate inconsistency in the naming of this thing.

Ah, right, I misread your post. DO WHILE is indeed a "normal" while loop. There doesn't seem to be an equivalent to "do { ... } while", as found in most C-style languages.

> There seems to be a unfortunate inconsistency in the naming of this thing.

Well, Fortran is older than C, so you cannot really blame them :-)

The funny thing is, I mostly program in Fortran (thus the interest in this construct). It is nice for expressing “this iterative method must be run at least once.” Unfortunately at some point I absorbed the name that comes from the C-ism, haha.

May I ask what field you're working in? Physics?

A less ambiguous name for those is repeat/until, as seen in Pascal and its descendants - I don't recall any language that uses that syntax for anything other than a postcondition loop.