3_2(delphi)

program lab3_2;
{$APPTYPE CONSOLE}
{$R *.res}
uses
  System.SysUtils;
const
    SetOfDigitsAndOperations = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '-', '*', '/', ':', '^', '√'];
type
    TCharSet = set of Char;

Function TakeSize: Integer;
const
    MIN_SIZE = 2;
    MAX_SIZE = 30;
var
    IsCorrect: Boolean;
    Number: Integer;
begin
    Number := 0;
    repeat
        IsCorrect := True;
        try
            Readln(Number);
        except
            Writeln('Incorrect input!!!');
            IsCorrect := False;
        end;
        if (IsCorrect and (Number < MIN_SIZE) or (Number > MAX_SIZE)) then
        begin
            Writeln('Incorrect input!!!');
            IsCorrect := False;
        end;
    until IsCorrect;
    TakeSize := Number;
end;

Function TakeChar: AnsiChar;
var
    IsCorrect: Boolean;
    InputChar: AnsiChar;
begin
    repeat
        IsCorrect := True;
        try
            Readln(InputChar);
        except
            Writeln('Incorrect input!!!');
            IsCorrect := False;
        end;
    until IsCorrect;
    TakeChar := InputChar;
end;

Function TakeSource: Byte;
const
    CHOOSING_CONSOLE = 1;
    CHOOSING_FILE = 2;
var
    Source: Byte;
    IsCorrect: Boolean;
begin
    Source := 0;
    repeat
        IsCorrect := True;
        try
            Readln(Source);
        except
            Write('Incorrect input!!! Select the source:' + #13#10 + '1:Console'  + #13#10 + '2:File'  + #13#10 + 'Enter 1 or 2: ');
            IsCorrect := False;
        end;
        if (IsCorrect and (Source <> CHOOSING_CONSOLE) and (Source <> CHOOSING_FILE)) then
        begin
            Write('Incorrect input!!! Select the source:' + #13#10 + '1:Console'  + #13#10 + '2:File'  + #13#10 + 'Enter 1 or 2: ');
            IsCorrect := False;
        end;
    until IsCorrect;
    TakeSource := Source;
end;

Function TakeInPath: String;
var
    Path: String;
    IsCorrect: Boolean;
    InFile: TextFile;
begin
    Write('Enter file path: ');
    repeat
        IsCorrect := True;
        Readln(Path);
        if not FileExists(Path) then
        begin
            Write('File is not found' + #13#10 + 'Enter file path: ');
            IsCorrect := False;
        end
        else
            if ((Path[Length(Path)] <> 't') or (Path[Length(Path) - 1] <> 'x') or
                (Path[Length(Path)- 2] <> 't') or (Path[Length(Path)- 3] <> '.')) then
            begin
                Write('File is found, but it is not ".txt" type file' + #13#10 + 'Enter file path: ');
                IsCorrect := False;
            end
            else
            begin
                Assign(InFile, Path);
                try
                    Reset(InFile);
                except
                    Write('Error!!! Program can''t open file!' + #13#10 + 'Enter file path: ');
                    IsCorrect := False;

                end;
            end;
    until IsCorrect;
    CloseFile(InFile);
    TakeInPath := Path;
end;

Function TakeOutPath: String;
var
    Path: String;
    IsCorrect: Boolean;
    OutFile: TextFile;
begin
    Write('Enter file path: ');
    repeat
        IsCorrect := True;
        Readln(Path);
        if ((Path[Length(Path)] <> 't') or (Path[Length(Path) - 1] <> 'x') or
            (Path[Length(Path)- 2] <> 't') or (Path[Length(Path) - 3] <> '.')) then
        begin
            Write('It should be a ".txt" type file' + #13#10 + 'Enter file path: ');
            IsCorrect := False;
        end
        else
        begin
            AssignFile(OutFile, Path);
            try
                Rewrite(OutFile);
            except
                Write('Error!!! There are problems with file!' + #13#10 + 'Enter file path: ');
                IsCorrect := False;
            end;
        end;
    until IsCorrect;
    CloseFile(OutFile);
    TakeOutPath := Path;
end;

Function TakeSetFromConsole: TCharSet;
var
    Size, i: Integer;
    CharSet: TCharSet;
    InputChar: AnsiChar;
begin
    Write('Enter size: ');
    Size := TakeSize;
    for i := 0 to (Size - 1) do
    begin
        Write('Enter element ', (i + 1), ': ');
        InputChar := TakeChar;
        Include(CharSet, InputChar);
    end;
    TakeSetFromConsole := CharSet;
end;

Function TakeSetFromFile(const Path: String): TCharSet;
const
    MIN_SIZE = 2;
var
    InFile: TextFile;
    Sign: AnsiChar;
    IsCorrect: Boolean;
    CharSet: TCharSet;
begin
    IsCorrect := True;
    AssignFile(InFile, Path);
    Reset(InFile);
    while(IsCorrect and (not Eof(InFile))) do
    begin
        try
            Read(InFile, Sign);
            Include(CharSet, Sign);
        except
            Writeln('Incorrect file content!!!');
            IsCorrect := False;
        end;
    end;
    if (IsCorrect and (not Eof(InFile))) then
    begin
        Writeln('Incorrect file content!!!');
        IsCorrect := False;
    end;
    if  not IsCorrect then
        CharSet := [];
    CloseFile(InFile);
    TakeSetFromFile := CharSet;
end;

Function TakeSet(Source: Byte): TCharSet;
var
    InPath: String;
    CharSet: TCharSet;
begin
    if (Source = 1) then
        CharSet := TakeSetFromConsole
    else
    begin
        InPath := TakeInPath;
        CharSet := TakeSetFromFile(InPath);
        while (CharSet = []) do
        begin
            InPath := TakeInPath;
            CharSet := TakeSetFromFile(InPath);
        end;
    end;
    TakeSet := CharSet;
end;

Function FindAnswers(CharSet: TCharSet): TCharSet;
var
    Answers: TCharSet;
begin
    Answers := CharSet * SetOfDigitsAndOperations;
    FindAnswers := Answers;
end;

Procedure OutputToConsole(Answers: TCharSet);
var
    Element: AnsiChar;
begin
    for Element in Answers do
        Write(Element, ' ');
end;

Procedure OutputToFile(const Path: String; Answers: TCharSet);
var
    OutFile: TextFile;
    Element: AnsiChar;
begin
    AssignFile(OutFile, Path);
    Rewrite(OutFile);
    for Element in Answers do
        Write(OutFile, Element, ' ');
    CloseFile(OutFile);
    Writeln('Done');
end;

Procedure Output(const Source: Byte; Answers: TCharSet);
var
    OutPath: String;
begin
    if (Source = 1) then
        OutputToConsole(Answers)
    else
    begin
        OutPath := TakeOutPath;
        OutputToFile(OutPath,Answers);
    end;
end;

var
    InputSource, OutputSource: Byte;
    InputSet: TCharSet;
    Answers: TCharSet;
begin
    Write('Welcome to the program that will print a set, whose elements are signs of arithmetic operations and digits from a given set' + #13#10+ 'Select the source for entering the array:'  + #13#10 + '1:Console'  + #13#10 + '2:File'  + #13#10 + 'Enter 1 or 2: ');
    InputSource := TakeSource;
    InputSet := TakeSet(InputSource);
    Answers := FindAnswers(InputSet);
    Write('Select the source for output:'  + #13#10 + '1:Console'  + #13#10 + '2:File'  + #13#10 + 'Enter 1 or 2: ');
    OutputSource := TakeSource;
    Output(OutputSource, Answers);
    Readln;
end.