Coder's Guild Mailing List

Re: Expression Matching and Recursion

Posted by Weasel on 1999-04-24

Eugene Teo wrote:
> 
> Hi
> 
> I am revising for my Advanced Data Structures module
> and i have got 2 important questions to ask. Please
> help.
> 
> Question 1:
> 
> (a+b(c+7)).

I've written a Pascal unit on this once. You may get it at our coder's
knowledge base:
www.netalive.org/ckb in the pascal/dos/math section. I use a tree
structure to parse it. It may not be that elegant but I did come up with
this myself a few years ago...

> Boolean IsPalindrome(char *s);
Recursive is a studip approach for this one but since you have to do it
this way, I'ld suggest sg like this:

function isPali(string) returns boolean
begin
  if firstletter=lastletter
    if length(string)=1 return true;
    return IsPale(string[1]-string[length-1]); (assuming the string
counts from zero, i.e. you pass the string without the last and without
the first character)
  else
    return false
  end;
end;


-- 
Weasel                          mailto:palfrader@xxxxxxx.xxx
Peter                   http://www.cosy.sbg.ac.at/~ppalfrad/
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