Prac_parentheses

uses UStack;

procedure Inp(var somestack: Stack);
var
    ifp: Text;
    parenthesis: char;
begin
    assign(ifp,'input.txt');
    reset(ifp);

    read(ifp,parenthesis);
    while (parenthesis <> '.') do
    begin
        somestack.push(parenthesis);
        read(ifp,parenthesis);
    end;

    close(ifp);
end;


procedure Outp(somestack: Stack);
var
    ofp: Text;
    tmp: Stack;
    null: char;
    flag: boolean;
begin
    tmp.Init;
    flag:= TRUE;
    while not (somestack.isEmpty) do
    begin
        if (somestack.top = ')') then
            tmp.push(somestack.pop)
        else
        begin
            null:= somestack.pop;
            if (tmp.isEmpty) then
            begin
                flag:= FALSE;
                break;
            end
            else
                null:= tmp.pop;
        end;
    end;

    assign(ofp,'output.txt');
    rewrite(ofp);
    if ((flag) and (tmp.isEmpty)) then
        writeln(ofp, 'TRUE')
    else
        writeln(ofp, 'FALSE');
    close(ofp);
end;

var
    mystack: Stack;
begin
    writeln;
    mystack.Init;
    writeln('start reading from file...');
    Inp(mystack);
    writeln('...finished'); writeln;

    writeln('start writing to file...');
    Outp(mystack);
    writeln('...finished'); writeln;
end.