DOMAINS

    list_string = string*
    number_list = integer*
    I = integer
    C = char

 PREDICATES

    nondeterm result
    nondeterm str_poisk(string,string)
    del_letter(char,string,string)
    str_pos(char,string,integer)
    str_delete(string,integer,integer,string)

 CLAUSES

        str_poisk("",Result):-
        nl,
        write(" Words with latin letters: "),nl,
        write(Result),nl.
        str_poisk(Sin,Letter):-
        frontchar(Sin,C,S1),
        del_letter(C,Letter,Result),
        str_poisk(S1,Result).

    del_letter(C,StrIn,StrOut):-
        str_pos(C,StrIn,Npos),
        Npos > 0, !, str_delete(StrIn,Npos,1,StrOut); str_delete(StrIn,1,0,StrOut).

        str_pos(C,S,1):-
        frontchar(S,C,_),!.

    str_pos(_,_,0).

    str_delete(S,I,C,SO) :-
        I1 = I - 1,
            frontstr(I1,S,S1,S2),
            frontstr(C,S2,_,S3),
            concat(S1,S3,SO).

        result:-
        nl, nl,
        write("   4. Check if there are words with latin letters in the string."), nl,
        write(" Enter the string: "),
        readln(Str),
        Letter = "abcdefghijklmnopqrstuvwxyz",
        str_poisk(Str,Letter),
        readchar(_),!.

 GOAL
        result.

PREDICATES

is_latin_letter(char).

check_string(string).
check_string(string, integer, integer). %i, i, o
between( integer, integer, integer ).

print_result(string, integer).


CLAUSES

is_latin_letter( Letter ) :-
    upper_lower( UpperCaseLetter, Letter ),
    char_int( UpperCaseLetter, Code),
    char_int('A',CodeA),
    char_int('Z',CodeZ),
    between(CodeA, CodeZ, Code).

  check_string( String ) :-
      check_string( String, 0, LatinLetterCount ),
      print_result( String, LatinLetterCount ).

  check_string("", N, N ).
  check_string( S, N1, N2 ) :-
      frontchar(S, Char, S1),
      if is_latin_letter( Char ) then
          M1 = N1 + 1
      else
          M1 = N1
      end if,
      check_string( S1, M1, N2 ).

between( Low, High, _Value ):-
     Low > High, !, fail.

between( Low, High, Low ).

between( Low, High, Value ):-
     NextLow is Low + 1,
     between( NextLow, High, Value).

 print_result(String, LatinLetterCount ):-
      str_len(String, Len),
      if LatinLetterCount = Len then
          write("Строка латинских букв =", String),
          write("Длина = ", Len).
      else
          write("Количество латинских букв в строке =", LatinLetterCount ).
      end if.

  GOAL

    check_string("B45X2FG0OP"),% Строка, содержащая произвольные символы.
    check_string("ABCdef").    % Строка, содержащая только прописные и строчные латинские буквы.