laba_2_3 (Delphi)

program laba_2_3;

{$APPTYPE CONSOLE}

uses
    SysUtils;

type
    TShortIntMatrix = array of array of ShortInt;

const
    MinNumber: ShortInt = -128;
    MaxNumber: ShortInt = 127;
    MinSize: ShortInt = 2;
    MaxSize: ShortInt = 127;

procedure GetOutputToConsole(Sum: Integer);
begin
    WriteLn('The sum is:', Sum);
end;

function GetAnswer(): Char;
var
    Answer: Char;
    IsCorrect: Boolean;
begin
    repeat
        ReadLn(Answer);
        Answer := UpCase(Answer);
        if (Answer = 'Y') or (Answer = 'N') then
            IsCorrect := true
        else
        begin
            IsCorrect := false;
            WriteLn('Incorrect input. Enter Y(Yes) or N(No):');
        end;
    until IsCorrect;
    GetAnswer := Answer;
end;

procedure GetOutputToFile(Sum: Integer);
var
    IsCorrect: Boolean;
    NewFile: TextFile;
    NameOfFile: String;
begin
    WriteLn('Enter the name of file Name.txt:');
    IsCorrect := false;
    repeat
        ReadLn(NameOfFile);
        if (not FileExists(NameOfFile)) then
            WriteLn('File does not exist. Try again:')
        else
        begin
            IsCorrect := true;
            Assign(NewFile, NameOfFile);
            writeln('Would you like to rewrite the file? Press Y(Yes) or N(No):');
            if GetAnswer = 'Y' then
                try
                    Rewrite(NewFile);
                    WriteLn(NewFile, 'The sum is:', Sum);
                except
                    WriteLn('Access is not allowed. Try again:');
                    IsCorrect:= false;
                end
            else
                try
                    Append(NewFile);
                    WriteLn(NewFile, 'The sum is:', Sum);
                except
                    WriteLn('Access is not allowed. Try again:');
                    IsCorrect:= false;
                end;
        end;
    until IsCorrect;
    Close(NewFile);
end;


function GetSum(Matrix: TShortIntMatrix; Size: ShortInt): Integer;
var
    Sum: Integer;
    i, j: ShortInt;
begin
    Sum := 0;
    for j := 0 to Size do
        for i := j + 1 to Size do
            if (Matrix[i, j] > 0) then
                    Sum := Sum + Matrix[i, j];
    GetSum := Sum;
end;

function CheckInput(Min, Max: ShortInt): ShortInt;
var
    IsCorrect: Boolean;
    Number: ShortInt;
begin
    IsCorrect := false;
    repeat
        try
            ReadLn(Number);
            if (Number >= min) and (Number <= max) then
                IsCorrect := true
            else
                WriteLn('Enter number from interval ', Min, '..', Max, ':');
        except
            WriteLn('Check entered data. Enter number from interval ', Min, '..', Max, ':');
        end;
    until IsCorrect;
    CheckInput := Number;
end;

function GetMatrixConsole(var Size: ShortInt): TShortIntMatrix;
var
    i, j: ShortInt;
    Matrix: TShortIntMatrix;
    IsCorrect: Boolean;
begin
    WriteLn('Enter size of matrix ', MinSize, '..', MaxSize, ':');
    Size := CheckInput(MinSize, MaxSize);
    SetLength(Matrix, Size, Size);
    Dec(Size);
    for i := 0 to Size do
        for j := 0 to Size do
        begin
            WriteLn('Enter [', i, '][', j, '] number of matrix ', MinNumber, '..', MaxNumber, ':');
            Matrix[i, j] := CheckInput(MinNumber, MaxNumber);
        end;
    GetMatrixConsole := Matrix;
end;

function CheckInputFile(const MinNumber, MaxNumber: ShortInt; var MyFile: TextFile): Boolean;
var
    IsCorrect: boolean;
    Number: ShortInt;
begin
    IsCorrect := true;
    while (not SeekEof(MyFile)) and (IsCorrect) do
        try
            ReadLn(MyFile, Number);
            if (Number <= MinNumber) or (Number >= MaxNumber) then
                IsCorrect := false;
        except
            IsCorrect := false;
        end;
    CheckInputFile := IsCorrect;
end;

function ReadFromFile(var MyFile: TextFile; var Matrix: TShortIntMatrix; var Size: ShortInt): Boolean;
var
    Number, i, j: ShortInt;
begin
    if CheckInputFile(MinNumber, MaxNumber, MyFile) then
    begin
        reset(MyFile);
        i := 0;
        while not Eof(MyFile) do
        begin
            SetLength(Matrix, i + 1);
            j := 0;
            while not Eoln(MyFile) do
            begin
                SetLength(Matrix[i], j + 1);
                Read(MyFile,Matrix[i,j]);
                WriteLn('Elemet [', i, '][', j, ']:', Matrix[i,j]);
                inc(j);
            end;
            ReadLn(MyFile);
            inc(i);
        end;
        if (i = j) then
        begin
            Size := i - 1;
            ReadFromFile := true;
        end
        else
        begin
            WriteLn('This is not a square matrix. Try again:');
            ReadFromFile := false;
        end;
    end
    else
    begin
        CloseFile(MyFile);
        ReadFromFile := false;
        WriteLn('Check entered data. Enter number from interval ', MinNumber, '..', MaxNumber, '. Try Again:');
    end;
end;

function GetMatrixFile(var Size: ShortInt): TShortIntMatrix;
var
    IsCorrect: Boolean;
    NameOfFile: String;
    MyFile: TextFile;
    Matrix: TShortIntMatrix;
begin
    WriteLn('Enter file name(Name.txt):');
    repeat
        ReadLn(NameOfFile);
        if (not FileExists(NameOfFile)) then
        begin
            WriteLn('File does not exist. Try again:');
            IsCorrect := false;
        end
        else
        begin
            AssignFile(MyFile, NameOfFile);
            reset(MyFile);
            if SeekEof(MyFile) then
            begin
                WriteLn('File is empty. Try again:');
                IsCorrect := false;
            end
            else
                IsCorrect := ReadFromFile(MyFile, Matrix, Size);
        end;
    until IsCorrect;
    CloseFile(MyFile);
    GetMatrixFile := Matrix;
end;

procedure Main();
var
    Matrix: TShortIntMatrix;
    Size: ShortInt;
    Sum: Integer;
begin
    WriteLn('This program calculates the sum of positive elements of a square matrix under the main diagonal.', #10, 'Would you like to open the file? Press Y(Yes) or N(No):');
    if GetAnswer = 'Y' then
        Matrix := GetMatrixFile(Size)
    else
        Matrix := GetMatrixConsole(Size);
    Sum := GetSum(Matrix, Size);
    WriteLn('Would you like to write down the answer to file? Press Y(Yes) or N(No):');
    if GetAnswer = 'Y' then
        GetOutputToFile(Sum)
    else
        GetOutputToConsole(Sum);
    WriteLn('Press "Enter" to exit the console.');
    ReadLn;
end;

begin
    Main();
end.