Re: "undefined behavior"?

From	Keith Thompson <Keith.S.Thompson+u@gmail.com>
Newsgroups	comp.lang.c
Subject	Re: "undefined behavior"?
Date	2024-06-14 18:39 -0700
Organization	None to speak of
Message-ID	<87r0cz3rx5.fsf@nosuchdomain.example.com> (permalink)
References	(3 earlier) <666a226d$0$951$882e4bbb@reader.netnews.com> <v4erpi$29e2g$2@dont-email.me> <666b0451$0$953$882e4bbb@reader.netnews.com> <v4hu1b$2ve93$3@dont-email.me> <666ccccb$0$973$882e4bbb@reader.netnews.com>

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DFS <nospam@dfs.com> writes:
[...]
> During conversion, I got a Python error I don't remember seeing in the past:
>
> "TypeError: list indices must be integers or slices, not float"
>
> because division returns a float, and some of the array addressing was
> like this: nums[i/2].
[...]

C's "/" operator yields a result with the type of the operands (after
promotion to a common type).

Python's "/" operator yields a floating-point result.  For C-style
integer division, Python uses "//".  (Python 2 is more C-like.)

See https://docs.python.org/3/ or comp.lang.python, which is reasonably
active.

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

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"undefined behavior"? DFS <nospam@dfs.com> - 2024-06-12 16:47 -0400
  Re: "undefined behavior"? Barry Schwarz <schwarzb@delq.com> - 2024-06-12 14:30 -0700
    Re: "undefined behavior"? DFS <nospam@dfs.com> - 2024-06-12 17:53 -0400
      Re: "undefined behavior"? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-06-12 15:30 -0700
        Re: "undefined behavior"? DFS <nospam@dfs.com> - 2024-06-12 19:07 -0400
          Re: "undefined behavior"? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-06-12 17:33 -0700
            Re: "undefined behavior"? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-06-13 05:47 +0100
              Re: "undefined behavior"? scott@slp53.sl.home (Scott Lurndal) - 2024-06-13 15:39 +0000
                Re: "undefined behavior"? Ben Bacarisse <ben@bsb.me.uk> - 2024-06-13 18:08 +0100
                Re: "undefined behavior"? bart <bc@freeuk.com> - 2024-06-13 19:01 +0100
                Re: "undefined behavior"? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-06-13 19:54 +0100
                Re: "undefined behavior"? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-06-13 12:34 -0700
                Re: "undefined behavior"? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-06-14 00:32 +0100
                Re: "undefined behavior"? Ben Bacarisse <ben@bsb.me.uk> - 2024-06-14 00:55 +0100
                Re: "undefined behavior"? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-06-14 02:48 +0100
                Re: "undefined behavior"? Ben Bacarisse <ben@bsb.me.uk> - 2024-06-14 12:44 +0100
                Re: "undefined behavior"? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-06-14 15:30 +0100
                Re: "undefined behavior"? Richard Harnden <richard.nospam@gmail.invalid> - 2024-06-14 16:32 +0100
                Re: "undefined behavior"? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-06-14 19:06 +0100
                Re: "undefined behavior"? bart <bc@freeuk.com> - 2024-06-14 19:31 +0100
                Re: "undefined behavior"? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-06-14 20:13 +0100
                Re: "undefined behavior"? Ben Bacarisse <ben@bsb.me.uk> - 2024-06-14 22:29 +0100
                Re: "undefined behavior"? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-06-14 23:35 +0100
                Re: "undefined behavior"? Ben Bacarisse <ben@bsb.me.uk> - 2024-06-15 00:14 +0100
                Re: "undefined behavior"? David Brown <david.brown@hesbynett.no> - 2024-06-15 20:57 +0200
                Re: "undefined behavior"? Richard Harnden <richard.nospam@gmail.invalid> - 2024-06-15 20:27 +0100
                Re: "undefined behavior"? Ben Bacarisse <ben@bsb.me.uk> - 2024-06-15 23:13 +0100
                Re: "undefined behavior"? David Brown <david.brown@hesbynett.no> - 2024-06-16 12:53 +0200
                Re: "undefined behavior"? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-06-16 14:44 +0100
                Re: "undefined behavior"? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-06-14 11:49 -0700
                Re: "undefined behavior"? Ben Bacarisse <ben@bsb.me.uk> - 2024-06-14 22:32 +0100
                Re: "undefined behavior"? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-06-15 00:56 -0700
                Re: "undefined behavior"? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-06-13 15:58 -0700
                Re: "undefined behavior"? bart <bc@freeuk.com> - 2024-06-14 02:18 +0100
                Re: "undefined behavior"? David Brown <david.brown@hesbynett.no> - 2024-06-14 19:08 +0200
                Re: "undefined behavior"? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-06-14 12:34 -0700
                Re: "undefined behavior"? David Brown <david.brown@hesbynett.no> - 2024-06-15 22:13 +0200
                Re: "undefined behavior"? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-06-14 13:43 -0700
              Re: "undefined behavior"? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-06-13 14:47 -0700
                Re: "undefined behavior"? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-06-14 00:41 +0100
                Re: "undefined behavior"? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-06-13 17:09 -0700
  Re: "undefined behavior"? David Brown <david.brown@hesbynett.no> - 2024-06-12 23:38 +0200
    Re: "undefined behavior"? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-06-12 15:18 -0700
      Re: "undefined behavior"? David Brown <david.brown@hesbynett.no> - 2024-06-13 14:42 +0200
        Re: "undefined behavior"? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-06-13 16:39 -0700
      Re: "undefined behavior"? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-06-18 17:23 -0700
        Re: "undefined behavior"? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-06-18 17:42 -0700
          Re: "undefined behavior"? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-06-22 09:28 -0700
    Re: "undefined behavior"? DFS <nospam@dfs.com> - 2024-06-12 18:29 -0400
      Re: "undefined behavior"? Ike Naar <ike@sdf.org> - 2024-06-13 07:25 +0000
        Re: "undefined behavior"? DFS <nospam@dfs.com> - 2024-06-13 11:13 -0400
          Re: "undefined behavior"? scott@slp53.sl.home (Scott Lurndal) - 2024-06-13 15:40 +0000
          Re: "undefined behavior"? Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2024-06-13 15:49 +0000
            Re: "undefined behavior"? DFS <nospam@dfs.com> - 2024-06-13 13:05 -0400
      Re: "undefined behavior"? David Brown <david.brown@hesbynett.no> - 2024-06-13 15:15 +0200
        Re: "undefined behavior"? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-06-13 16:47 -0700
          Re: "undefined behavior"? David Brown <david.brown@hesbynett.no> - 2024-06-14 19:13 +0200
  Re: "undefined behavior"? Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-06-12 23:38 +0200
    Re: "undefined behavior"? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-06-12 15:22 -0700
      Re: "undefined behavior"? DFS <nospam@dfs.com> - 2024-06-12 18:34 -0400
        Re: "undefined behavior"? David Brown <david.brown@hesbynett.no> - 2024-06-13 15:21 +0200
          Re: "undefined behavior"? DFS <nospam@dfs.com> - 2024-06-13 10:38 -0400
            Re: "undefined behavior"? David Brown <david.brown@hesbynett.no> - 2024-06-14 19:18 +0200
              Re: "undefined behavior"? scott@slp53.sl.home (Scott Lurndal) - 2024-06-14 17:36 +0000
                Re: "undefined behavior"? David Brown <david.brown@hesbynett.no> - 2024-06-15 22:15 +0200
              Re: "undefined behavior"? DFS <nospam@dfs.com> - 2024-06-14 19:05 -0400
                Re: "undefined behavior"? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-06-14 18:39 -0700
                Re: "undefined behavior"? DFS <nospam@dfs.com> - 2024-06-14 23:49 -0400
                Re: "undefined behavior"? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-06-14 20:56 -0700
                Re: "undefined behavior"? DFS <nospam@dfs.com> - 2024-06-15 00:45 -0400
                Re: "undefined behavior"? Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-06-15 07:03 +0200
                Re: "undefined behavior"? DFS <nospam@dfs.com> - 2024-06-15 07:39 -0400
                Re: "undefined behavior"? James Kuyper <jameskuyper@alumni.caltech.edu> - 2024-06-15 01:05 -0400
                Re: "undefined behavior"? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-06-14 22:20 -0700
                Re: "undefined behavior"? bart <bc@freeuk.com> - 2024-06-15 09:37 +0100
                Re: "undefined behavior"? David Brown <david.brown@hesbynett.no> - 2024-06-15 22:22 +0200
      Re: "undefined behavior"? Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-06-13 02:19 +0200
        Re: "undefined behavior"? David Brown <david.brown@hesbynett.no> - 2024-06-13 15:28 +0200
  Re: "undefined behavior"? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-06-12 14:57 -0700
  Re: "undefined behavior"? bart <bc@freeuk.com> - 2024-06-13 10:43 +0100
  Re: "undefined behavior"? Bonita Montero <Bonita.Montero@gmail.com> - 2024-06-13 11:45 +0200

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