program lab2_5;

uses
    System.SysUtils;

Type
    Stack = array[1..100] of Char;

function GetOpen(const aCh: Char): Char;
begin
    case aCh of
        ')': GetOpen := '(';
        ']': GetOpen := '[';
        '}': GetOpen := '{';
    else
        GetOpen := '*';
    end;
end;

function Proc(var StackPnt: Integer; StrSrc: String): Boolean;
var
    i: Integer;
    Ch: Char;
    Balance: Boolean;
    MassStack: Stack;
const
    D1 = ['(', '[', '{'];
    D2 = [')', ']', '}'];
begin
    StackPnt := 1;
    i := 1;
    Balance := True;
    while (i <= length(StrSrc)) and Balance do
    begin
        if StrSrc[i] in D1 then
        begin
            MassStack[StackPnt] := StrSrc[i];
            inc(StackPnt);
        end
        else
            if StrSrc[i] in D2 then
            begin;
                dec(StackPnt);
                Ch := MassStack[StackPnt];
                if Ch <> GetOpen(StrSrc[i]) then
                    Balance := False;
            end;
        inc(i);
    end;
    Proc := (StackPnt = 1);
end;

function isStrCorrect(StrSrc: String): Boolean;
var
    i: integer;
    isCorrect: boolean;
const
    D1 = ['(', '[', '{'];
    D2 = [')', ']', '}'];
begin
    isCorrect := false;
    for i := 1 to length(StrSrc) do
        if StrSrc[i] in D1 then
            isCorrect := true
        else
            if StrSrc[i] in D2 then
                isCorrect := true;
    isStrCorrect := isCorrect;
end;

function FileNameInputRead(): string;
var
    isCorrect: boolean;
    FileName: string;
begin
    isCorrect := false;
    repeat
        writeln('Enter file name:');
        readln(FileName);
        if FileExists(FileName) then
            isCorrect := true
        else
            writeln('This file does not exist!');
    until isCorrect;
    FileNameInputRead := FileName;
end;

procedure IsBracketCorrect();
var
    FileIn: TextFile;
    FileName, StrSrc: string;
    StackPnt: Integer;
begin
    FileName := FileNameInputRead();
    Assign(FileIn, Filename);
    Reset(FileIn);
    while not eof(FileIn) do
    begin
        readln(FileIn, StrSrc);
        writeln(StrSrc);
        if isStrCorrect(StrSrc) then
            if Proc(StackPnt, StrSrc) then
                Writeln('Brackets agreed.')
            else
                Writeln('Brackets are not agreed.')
        else
            Writeln('There are no brackets in the line!');
    end;
    close(FileIn);
end;

begin
    writeln('This program will check the balance of the brackets in the lines');
    IsBracketCorrect();
    readln;
end.