Во всех словах заменить первую букву на последнюю, а последнюю на первую. Как считывать каждое слово? - Turbo Pascal

Program Files;
Uses crt;
 
Procedure Input(Var S: string; Var f1: text);
Var i:shortint;
    n:integer;
    M:string;
begin
 Write('Enter the file name: ');
 Readln(M);
 Assign(f1, M);
 {$I-}
  Rewrite(f1);
 {$I+}
 if ioresult <> 0 then
  WriteLn('File not found')
 else
  begin
   WriteLn('Found file');
   Rewrite(f1);
 Write('Enter number the strings (0<Strings<=10): ');
 Readln(n);
 Repeat
  if (n>10) or (n<1) then
   begin
    write('Incorrect, retype please: ');
    readln(n);
   end;
 Until (n>=1) and (n<=10);
 for i:=1 to n do
  begin
   Write('Enter string #[',i,']: ');
   readln(s);
   writeln(f1,s);
  end;
 close(f1);
 writeln;
end;
end;
 
Procedure ReplaceLetters(Var s:string; Var f1,f2: text);
Var i:shortint;
    c:char;
begin
 Reset(f1);
 Assign(f2, 'file2.txt');
 Rewrite(f2);
 writeln('File1: ');
 while not eof(f1) do
  begin
   readln(f1,s);
   writeln(s);
   c:=s[1];
   s[1]:=s[Length(s)];
   s[Length(s)]:=c;
   writeln(f2,s);
  end;
 Close(f1);
 Close(f2);
end;
 
Procedure Output(Var S: string; Var f2: text);
begin
 Writeln;
 Writeln('File2: ');
 Reset(f2);
 While not eof(f2) do
 begin
  begin
   readln(f2,s);
   Writeln(s);
  end;
 end;
end;
 
Var File1,File2: text;
    Lines: string;
 
Begin
 clrscr;
 writeln('Program to replace the first and last letters in words to each other');
 Input(Lines,File1);
 ReplaceLetters(Lines,File1,File2);
 Output(Lines,File2);
 write('The program is completed, press any key to exit . . .');
 readkey;
End.