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From: PHARMAIL%RUG.NL@uga.cc.uga.edu
Newsgroups: comp.lang.pascal
Subject: RE: Anagram
Message-ID: <25420@adm.brl.mil>
Date: 8 Jan 91 13:42:59 GMT
Sender: news@adm.brl.mil
Lines: 54

{
Hi netlanders,
some time ago, while studying recursion, I made the following program
in Turbo Pascal. Recursion is great!
I think it produces anagrams.
What kind of magazine is _SPY_? Never heard of it.
Please let me know.
Greetings, Paul
}

program anagram;
{
  recursive calculation of permutations
  Author: Paul B. van den Berg - PHARMAIL@rc.rug.nl
}

const
 maxL = 8;
type
 charray = string[maxL];
var
 st: charray;
 count: longint;
 n: integer;
 ch: char;

procedure permutate(x: integer; var st: charray);
 var i, j: integer; st2: charray;
begin
 if x=1 then
 begin
  inc(count); write(' ',st)
 end
 else
 begin
  dec(x); j:=n-x;
  if x=2 then writeln;
  permutate(x,st);
  for i:=j+1 to n do
  begin
   st2:=st; ch:=st2[j]; st2[j]:=st[i]; st2[i]:=ch; permutate(x,st2)
  end
 end
end;

begin
 writeln(' RECURSIVE CALCULATION of PERMUTATIONS ');
 writeln;
 write('Input some string (max ',maxL,' letters): '); readln(st);
 count:=0;
 n:=length(st);
 permutate(n,st);
 writeln; writeln(count,' permutations');
end.