countunit.pas

利用多边形无限接近圆的方法计算π值

unit CountUnit;

interface

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

type
  TForm1 = class(TForm)
    Button1: TButton;
    Memo1: TMemo;
    Memo2: TMemo;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
var m:Extended;a,s,s1,h:Extended;
begin
a:=1;m:=6;
s:=3*sqrt(3)/2;
repeat
memo1.Lines.Add(FloatToStr(m));
memo2.Lines.Add(FloatToStr(S));
s1:=s;
h:=1-sqrt(1-a*a/4);
s:=s+m*a*h/2;
a:=sqrt(h*h+a*a/4);
m:=m*2;
until abs(s-s1)<=1e-20;
end;

end.