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5400 discussions

ok!
by Nathalie Jarosz 27 May '00

27 May '00

Hi again again! I manage to get my e_mail back. So, don't take into account my previous mail! Thanks a lot for your numerous answers about random, I will try immediately! Nathalie

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random again
by Nathalie Jarosz 27 May '00

27 May '00

Hi! Could you send me again your answer because I had troubles with my e_mail yesterday.. thanks, Nathalie

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Re: random
by Frank Heckenbach 27 May '00

27 May '00

Marco van de Voort wrote: > > In GPC, in may be very large, e.g.: > > <snip> > > > a := Random (1000000000000000000); > > Random has a 64-bit definition? Or both 64 and 32 with overloading? The internal RNG is 32 bit, but is a 64 bit number is wanted, Random calls it twice. The `Random' function is overloaded (with compiler magic) for LongestReal and LongestCard (i.e., the longest available real and (unsigned) integer types -- this may by 64 bit, or 128 … [View More]

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Re: random
by Frank Heckenbach 26 May '00

26 May '00

George Shapovalov wrote: > var N:any_integer_type; (may be not extended (very large) integer integer) > random(N); would return integer type in the range 0..N-1 In GPC, in may be very large, e.g.: program Foo; var a : LongInt; begin a := Random (1000000000000000000); Writeln (a) end. > random; (without parameters) would return float in the range 0..1. (with 0 inclusively and 1 exclusively) Frank -- Frank Heckenbach, frank(a)g-n-u.de, http://fjf.gnu.de/ GPC To-Do list, … [View More]

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random
by Nathalie Jarosz 26 May '00

26 May '00

Hi, I'd like to use random numbers generator. Is someone knows some efficient procedures or functions in pascal? Thanks a lot in advance for your help, Nathalie

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Re: revised faq
by Frank Heckenbach 26 May '00

26 May '00

Hi, after Russ Whitaker has updated the FAQ (thanks!), I've discovered a problem: The old version of the FAQ was written in Texinfo. A version translated to ASCII was distributed with GPC, and that's proabably all you've seen, Russ, and consequently edited this version. Now, it would be nice to have the current FAQ in Texinfo format again. Then we could, e.g., provide an HTML version on the GPC home page and include it into GPC's documentation (and it could also contain direct cross-links to … [View More]

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Re: possible bug question...
by Frank Heckenbach 26 May '00

26 May '00

Russ Whitaker wrote: > Does the Standards Committiee still exist? I think the members meet at irregular time intervals. Some (or at least one) of them is reading c.l.p.a-i, so you might want to post there... > It would be nice to > start the ball rolling tward a rewrite, even if nothing more than > a conversion into real english. Unlikely. However, be invited to help improving the GPC documentation where real English descriptions of this and many other features are urgently … [View More]

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Re: possible bug question...
by Russ Whitaker 25 May '00

25 May '00

Hi Sounds like someone tried to define Pascal by using a Flow Chart and someone else converted the Flow Chart itself into english :-) Does the Standards Committiee still exist? It would be nice to start the ball rolling tward a rewrite, even if nothing more than a conversion into real english. In the meanwhile, just for fun patched the original program that started this thread: program prime1; {find prime numbers up to 100} var i,j,k: integer; begin for i := 2 to 100 do begin k … [View More]

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Re: posible bug question...
by Frank Heckenbach 24 May '00

24 May '00

J. David Bryan wrote: > On 20 May 2000, at 9:31, Russ Whitaker wrote: > > > So what does the Pascal specs say? > > The Extended Pascal standard, section 6.9.3.9.1, says: > > "After a for-statement is executed, other than being left by a > goto-statement, the control-variable shall be undefined." > > That's remarkably clear. :-) That means that variable "b" in the code > below isn't guaranteed to be true: In fact, i = 10 in the current GPC … [View More]version (but don't rely on it :-). > procedure p; > var i : integer; > b : Boolean; > begin > for i := 1 to 10 do ; > b := (i > 10); > end; > The next part of the standard is a bit less clear: > > "Neither a for-statement nor any procedure-and-function-declaration-part > of the block that closest-contains a for-statement shall contain a > statement threatening (see 6.9.4) a variable-access denoting the > variable denoted by the control-variable of the for-statement." > > I believe that says that you can't modify the control variable of a for- > statement (a "threat" is defined in the standard as one of ten ways that a > variable may be assigned a value). Including a `for' statement (item g :-). Therefore I conclude that a `for' statement by itself is illegal in Pascal. Alright, we'll take it out of the next GPC release. Just kidding... > So this would clearly be illegal: > > procedure p; > var i : integer; > begin > for i := 1 to 10 do > i := 11; > end; > > However, it also says that a block containing a for-statement cannot > contain a threat to the control variable. In other words, this would be > illegal too: > > procedure p; > var i : integer; > begin > i := 0; > for i := 1 to 10 do > end; > > I suppose the reason is to disallow something like this: > > procedure p; > var i : integer; > label 1, 2, 3; > begin > goto 1; > 2: i := 11; > goto 3; > > 1: for i := 1 to 10 do > begin > goto 2; > 3: > end > end; > > ...which is functionally equivalent to the second code example. Yes, but is a goto into a loop legal at all (the last sentence of 6.9.2.4 seems to indicate not to me, but I'm not completely sure)? If it is legal, what should the following code do? procedure p; var i : integer = 42; label 1; begin goto 1; for i := 1 to 10 do begin 1: Writeln (i) end end; > So it would seem that to comply with the EP standard, GPC must prohibit any > threat (i.e., variable assignment) to a for-statement control variable > anywhere within the scope of that variable, and not just within the for- > statement itself. This would mean that the loop variable could practically not be used outside of the for loop. If this is really true, I'd really favour a syntax that makes this clear (like `for i : Integer = 1 to 10 do ...'), so i has only the corresponding scope. Frank -- Frank Heckenbach, frank(a)g-n-u.de, http://fjf.gnu.de/ GPC To-Do list, latest features, fixed bugs: http://agnes.dida.physik.uni-essen.de/~gnu-pascal/todo.html [View Less]

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Re: posible bug question...
by Frank Heckenbach 24 May '00

24 May '00

J. David Bryan wrote: > Hello Marco, > > I have copied my reply to the list. > > > On 21 May 2000, at 15:56, Marco van de Voort wrote: > > > Or do they mean: > > > > procedure x; > > > > var i : integer; > > > > procedure nestedx; > > > > begin > > i:=5; > > end; > > > > begin > > for i:=1 to 5 do nestedx; > > end; > > I believe you are correct, and my original … [View More]

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