Discrete Fourier Transform

It's not flexible one.

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, Buttons, Grids;

type
  TForm1 = class(TForm)
    StringGrid1: TStringGrid;
    BitBtn1: TBitBtn;
    Edit1: TEdit;
    procedure proses;
    procedure BitBtn1Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure tform1.proses;
var i,j:integer;
fm:real;
begin
  for i:=0 to 50 do begin
    fm:=0;
    for j:=0 to 10 do begin
     {untuk fungsi rect(x)}
     fm:=fm+1*cos(2*PI*j*i/10/11);
    end;
    stringgrid1.Cells[0,i+1]:=floattostr(i);
    stringgrid1.Cells[1,i+1]:=floattostr(i/10);
    stringgrid1.Cells[2,i+1]:=floattostr(fm);
    edit1.Text:=floattostr(fm);
    application.ProcessMessages;sleep(200);
    f(x)=cos(x)+cos(2x)+cos(3x)+cos(4x)}
  end;
end;

procedure TForm1.BitBtn1Click(Sender: TObject);
begin
  proses;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  stringgrid1.RowCount:=51;
  stringgrid1.Cells[0,0]:='no';
  stringgrid1.Cells[1,0]:='m';
  stringgrid1.Cells[2,0]:='f[m]';
  //stringgrid1.Cells[3,0]:='no';
end;

end.