unit Unit1;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, StdCtrls,
  Grids;

type
  Matr = Array[1..5,1..5] of Real;
Vec = Array[1..5] of Real;
  { TForm1 }

  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    Edit1: TEdit;
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    Label4: TLabel;
    StringGrid1: TStringGrid;
    StringGrid2: TStringGrid;
    StringGrid3: TStringGrid;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    { private declarations }
  public
    { public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.lfm}

{ TForm1 }

procedure TForm1.FormCreate(Sender: TObject);
begin

end;

procedure TForm1.Button3Click(Sender: TObject);
begin
  close
end;

procedure TForm1.Button1Click(Sender: TObject);
Var N: Integer;
Begin
N := StrToInt(Edit1.Text);
StringGrid1.ColCount := N;
StringGrid1.RowCount := N;
StringGrid2.rowCount := N;
StringGrid3.rowCount := N;
end;

  procedure TForm1.Button2Click(Sender: TObject);
  Var A : Matr;
  b, x : Vec;
  i, j, k, p, n: integer;
  m, S, t: real;
  begin
  N := StrToInt(Edit1.Text);
  For i:=1 to N do
  For j:=1 to N do
  Begin
  a[i,j] := StrToFloat(StringGrid1.Cells[j - 1,i - 1]);
  b[j] := StrToFloat(StringGrid2.Cells[0,j - 1]);
  End;
begin
k:= 1;
while true do
begin
i:= k + 1;
if (a[k, k] = 0) then
begin
{перестановка}
p:= k;
while true do
begin
if abs(a[i, k]) > abs(a[p, k]) then p:= i;
if i = n then break;
i:= i + 1;
continue;
end;
if p= k then i:= k + 1
else
begin
j:= k;
while true do
begin
t:= a[k, j];
a[k, j]:= a[p, j];
a[p, j]:= t;
if j = n then break;
j:= j + 1;
continue;
end;
t:= b[k];
b[k]:= b[p];
b[p]:= t;
end;
end; // кінець перестановки
while true do
begin
m:=a[i, k] / a[k, k];
a[i, k]:= 0;
j:= k + 1;
while true do
begin
a[i, j]:= a[i, j] - m * a[k, j];
if j = n then break;
j:= j + 1;
continue;
end;
b[i]:= b[i] - m * b[k];
if i = n then break;
i:= i + 1;
continue;
end;
if k= n - 1 then break;
k:= k + 1;
continue;
end;
{Перевіряємо чи існує корінь}
if a[n, n] <> 0 then
begin
x[n]:= b[n] / a[n, n];
i:= n - 1;
while true do
begin
j:= i + 1;
S:= 0;
while true do
begin
S:= S - a[i, j] * x[j];
if j = n then break;
j:= j + 1;
continue;
end;
x[i]:= (b[i] + S) / a[i, i];
if i = 1 then break;
i:= i - 1;
continue;
end;
  For i:=1 to N do
  Begin
  StringGrid3.Cells[0,i-1]:=FloatToStr(x[i]);
  End;
end
else
if b[n] = 0 then
ShowMessage('Systema rivnyannya ne maye rozv''yazkiv')
else
ShowMessage('bezlich rozvyazkiv');
ShowMessage('press any key');
end;
end;
end.

end;

end.