StrUtils

unit StrUtils;

interface

function GetWordsCount(Str: string): integer;
function GetWordById(Str: string; Id: integer): string;
function DeleteWordById(Str: string; Id: integer): string;

implementation

function GetWordsCount(Str: string): integer;
const
  letters : set of char =
   ['A'..'z', 'a'..'z', 'А'..'Я', 'а'..'я', 'Ё', 'ё'];
var
  found: boolean;
  i: integer;
begin
  Result := 0;
  i := 1;
  repeat
    found := false;
    while (i <= Length(Str))and(not(Str[i] in letters)) do
      inc(i);
    while (i <= Length(Str))and(Str[i] in letters) do begin
      found := true;
      inc(i);
    end;
    if found then
      inc(Result);
  until (i >= Length(Str))or(not found);
end;

function GetWordById(Str: string; Id: integer): string;
const
  letters : set of char =
   ['A'..'z', 'a'..'z', 'А'..'Я', 'а'..'я', 'Ё', 'ё'];
var
  i, k: integer;
begin
  Result := '';
  i := 1;
  k := 1;
  repeat
    Result := '';
    while (i <= Length(Str))and(not(Str[i] in letters)) do
      inc(i);
    while (i <= Length(Str))and(Str[i] in letters) do begin
      if (k = Id) then
        Result := Result+Str[i];
      inc(i);
    end;
    inc(k);
  until (i >= Length(Str))or(k = Id+1);
end;

function DeleteWordById(Str: string; Id: integer): string;
const
  letters : set of char =
   ['A'..'z', 'a'..'z', 'А'..'Я', 'а'..'я', 'Ё', 'ё'];
var
  i, k, n: integer;
begin
  Result := '';
  i := 1;
  k := 1;
  repeat
    Result := '';
    n      := 0;
    while (i <= Length(Str))and(not(Str[i] in letters)) do
      inc(i);
    while (i <= Length(Str))and(Str[i] in letters) do begin
      if (k = Id) then
        inc(n);
      inc(i);
    end;
    if n <> 0 then
      Delete(Str, i-n, n);
    inc(k);
  until (i >= Length(Str))or(k = Id+1);
  Result := Str;
end;

end.


{=========== example ===========}
//writeln(GetWordsCount('one two three'));
//writeln(GetWordById('one two three', 3));
//writeln(DeleteWordById('one two three', 2));