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***drdebcol*** · 06-13-2009, 02:39 AM

This is competitive assignment, and it is about finding the longest palindrome in the word.
Palindrome is a word that you read the same from both sides.
Example :
radar

***drdebcol*** · 06-15-2009, 03:25 AM

This is complex issue if you want to make it right !
It is easy to make it to check palindrome for words, but for
whole sentences is a bit harder, but if you add the fact that
in the sentence could be lower case and upper case characters,
then you get a complex assignment !
Basically there are 3 functions :

Code:

lower_case_string(string)

del_separations(string)

palindrome_check(string)

First function makes whole string lower case !
It checks if string is upper case and then converts it to lowercase !
Second function deletes separations from string (if string is sentence and it has " " characters or spaces).
This function is a recursion, you can see that in this line:

Code:

del_separations:=del_separations(copy(s,1,k1)+copy(s,k+1,length(s)));

And palindrome_check is the main function in program, and
if just turn the string over and checks if it is the same like enter string, and returns boolean !
So here is the solution in TPW :

Code:

program the_longest_palindrome;

uses wincrt;

var

 s,max,temp:string;

 i,j:integer;

 label top;

function lower_case_string(s:string):string;

var

 i:integer;

begin

  for i := 1 to length(s) do

    if (s[i] >='A') and (s[i]<='Z') then

      inc(s[i], 32);

  lower_case_string:=s;

end;

function del_separations(s:string):string;

var

 k:integer;

begin

  k:=pos(' ',s);

  if k=0 then

    del_separations:=s

  else

    del_separations:=del_separations(copy(s,1,k-1)+copy(s,k+1,length(s)));

end;

function palindrome_check(s:string):boolean;

var

 i:integer;

 temp:string;

begin

    temp:='';

   for i:=length(s) downto 1 do

      temp:=temp+s[i];

   if temp=s then

     palindrome_check:=true

   else

     palindrome_check:=false;

end;

begin

top:

writeln('---------------------------------');

writeln('-Program for finding the longest-');

writeln('-    palindrome by Dr DEBCOL    -');

writeln('---------------------------------');

writeln('Enter the word or sentence ?');

readln(s);

s:=lower_case_string(del_separations(s));

max:='';

for i:=1 to length(s) do

  for j:=i to length(s) do

    begin

      temp:=copy(s,i,j);

      if palindrome_check(temp) then

        if length(temp)>length(max) then

          max:=temp;

    end;

if length(max)=1 then

  writeln('This word or sentence does not have palindroms in it !')

else

  writeln('The longest palindrome is ',max);

writeln;

writeln('Press Enter if you want to try again !');

readln;

clrscr;

goto top;

end.

And in Free Pascal IDE :

Code:

program the_longest_palindrome;

var

 s,max,temp:string;

 i,j:integer;

 label top;

function lower_case_string(s:string):string;

var

 i:integer;

begin

  for i := 1 to length(s) do

    if (s[i] >='A') and (s[i]<='Z') then

      inc(s[i], 32);

  lower_case_string:=s;

end;

function del_separations(s:string):string;

var

 k:integer;

begin

  k:=pos(' ',s);

  if k=0 then

    del_separations:=s

  else

    del_separations:=del_separations(copy(s,1,k-1)+copy(s,k+1,length(s)));

end;

function palindrome_check(s:string):boolean;

var

 i:integer;

 temp:string;

begin

    temp:='';

   for i:=length(s) downto 1 do

      temp:=temp+s[i];

   if temp=s then

     palindrome_check:=true

   else

     palindrome_check:=false;

end;

begin

top:

writeln('---------------------------------');

writeln('-Program for finding the longest-');

writeln('-    palindrome by Dr DEBCOL    -');

writeln('---------------------------------');

writeln('Enter the word or sentence ?');

readln(s);

s:=lower_case_string(del_separations(s));

max:='';

for i:=1 to length(s) do

  for j:=i to length(s) do

    begin

      temp:=copy(s,i,j);

      if palindrome_check(temp) then

        if length(temp)>length(max) then

          max:=temp;

    end;

if length(max)=1 then

  writeln('This word or sentence does not have palindroms in it !')

else

  writeln('The longest palindrome is ',max);

writeln;

writeln('Press Enter if you want to try again !');

readln;

clrscr;

goto top;

readln;

end.