program lab2_3;

{$APPTYPE CONSOLE}

{$R *.res}

uses
    System.SysUtils;

type
    MassType = array of array of double;

procedure MatrixIterations(var Matrix: MassType; StrokStart, StolbStart, StrokEnd, StolbEnd: integer);
var
    MnojStr : double;
    i, j: integer;
begin
    for i := StrokStart to StrokEnd do
    begin
        MnojStr := (Matrix[i, StolbStart] / Matrix[StolbStart, StolbStart]) * -1;
        for j := StolbStart to StolbEnd do
            Matrix[i, j] := Matrix[i, j] + Matrix[StolbStart, j] * MnojStr;
    end;
end;

procedure MatrixOutput(const Matrix: MassType; Strok, Stolb: integer);
var
    i, j: integer;
begin
    for i := 0 to Strok do
    begin
        for j := 0 to Stolb do
            write(Matrix[i, j]:6:3, ' ');
        writeln;
    end;
    writeln;
end;

function ReadFile(var Matrix: MassType; Path : string; StrokEnd, StolbEnd: integer): MassType;
var
    FileIn: TextFile;
    i, j: integer;
begin
    AssignFile(FileIn, Path);
    reset(FileIn);
    while (not EOF(FileIN)) do
    for i := 0 to StrokEnd do
        for j := 0 to StolbEnd do
            read(FileIn, Matrix[i, j]);
    CloseFile(FileIn);
end;

procedure WriteFile(const Matrix: MassType; Path : string; StrokEnd, StolbEnd: integer);
var
    FileOut: TextFile;
    i, j: integer;
begin
    AssignFile(FileOut, Path);
    rewrite(FileOut);
    for i := 0 to StrokEnd do
    begin
        for j := 0 to StolbEnd do
        begin
            write(FileOut, Matrix[i, j]:6:3);
            write(FileOut, '    ');
        end;
    writeln(FileOut, ' ');
    end;
    CloseFile(FileOut);
end;

var
    FileIn, FileOut:  TextFile;
    Matrix: MassType;
    i, j, StrokStart, StolbStart: integer;

const
    StolbEnd = 4;
    StrokEnd = 3;
    NumOfIterations = 2;

begin
    SetLength(Matrix, StrokEnd + 1, StolbEnd + 1);
    ReadFile(Matrix, 'FileIN.txt', StrokEnd, StolbEnd);
    MatrixOutput(Matrix, StrokEnd, StolbEnd);
    StrokStart := 1;
    StolbStart := 0;
    for i := 0 to NumOfIterations do
    begin
        MatrixIterations(Matrix, StrokStart, StolbStart, StrokEnd, StolbEnd);
        inc(StrokStart);
        inc(StolbStart);
    end;
    MatrixOutput(Matrix, StrokEnd, StolbEnd);
    WriteFile(Matrix, 'FileOut.txt', StrokEnd, StolbEnd);
    readln;
end.