🚀 go-pugleaf

br-pede@online.no wrote:
> 
> I am trying to make a software, where the user can put in some word, and the
> program will look and see if the word(s) is in a wordlist file. Everything
> is working pretty well, except this: The procedure is running in a recursive
> way, that if you want to look up more than one word, you only put it in next
> time you are asked. To exit this, you only have to input an empty string,
> that is to press the ENTER key. And here is the trouble. The program will
> not stop this looping, unless you enter several empty words.
> 
> Here is the snip of the program that is causing trouble:
> 
> procedure lookup;
> begin
>     writeln;
>     write('please enter word to be looked up: ');
>     readln( s ); { s : STRING; }
>     if s = '' then exit; { this doesn't work,
>                            unless running a couple of
>     assign(f,'wordlist.dat'); reset(f);
>     repeat
>          read(f,t); { t : STRING }
>          if t = s then found := true   else found := false; {found : BOOLEAN}
>     until eof(f);
>     close(f); {f : FILE OF STRING}
>     if not found then begin
>          writeln('the word ', s, 'is not found in the list');
>          lookup;
>       end;{if}
>     writeln('the word ', s, ' is found in the list');
> end;{ procedure lookup}
> 
> Begin
>     { call a menu}
>     Repeat read(keychoice) until keychoice in [#0 .. #255];
>     { keychoice : CHAR }
>     if keychoice = '1' then lookup;
>     { call the menu}
>     ...
> end.


I don't see a need for "lookup" to call itself.  Try the following:

 procedure Lookup;
   const WORDLIST_FILE = 'wordlist.dat';
 begin
     assign(f,WORDLIST_FILE);
     reset(f);
     if eof(f) then
          writeln('Wordlist file ',WORDLIST_FILE,' is empty')
     else
     begin (* f is not empty *)
          writeln;
          write('Please enter word to be looked up or just Enter to
quit: ');
          readln( s ); { s : STRING; }

          repeat (* find the word and get new word to find until empty
string entered *)
               reset(f); (* reset the wordlist file to do further
lookups *)
               found := false;

               repeat (* try to find the word *)
                    readln(f,t);
                    found := (t = s);
               until found or eof(f);

               write('The word ',s,' is ');
               if not(found) then write('not ');
               writeln('found in the list');
               writeln;
               write('Please enter word to be looked up or just Enter to
quit: ');
               readln( s ); { s : STRING; }
          until s = ''; (* find the word, get new word to find until
empty string entered *)

     end; (* f is not empty *)
     close(f);
 end; (* Lookup *)

Ideally, you'd want some error-checking to make sure you could open the
wordlist file.  I suspect that many variables like "found", "s", and "t"
don't need to be global.  

Personally, I'd change some of the redundant code I posted above to be a
procedure declared inside "Lookup" as well as the repeat loop which
tries to find the matching word.  I'd also make the variable names
longer and more descriptive of their usage.