unit1.~pas

本光盘是《Delphi 7应用教程》一书的配套光盘

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Label1: TLabel;
    Label2: TLabel;
    Edit1: TEdit;
    Label4: TLabel;
    Edit2: TEdit;
    Label5: TLabel;
    Edit3: TEdit;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}
var             //定义两个全局变量
  s:Real;
  n:Integer;
procedure ryjd(k:Integer);
var
  r,t:Real;
  j:Integer;
begin
  s:=1;
  n:=1;
  j:=-1;
  r:=exp(k*Ln(0.1)); //表示小数点后有效位数为k
  Repeat
    t:=s;
    j:=j*(-1);
    n:=n+1;
    s:=s-j/((n-1)*n);
  Until abs(s-t)<=r; //满足要求的精度即中断循环
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  m:Integer;
begin
  m:=StrToInt(Edit1.Text);
  ryjd(m);
  Edit2.Text:=IntToStr(n);
  Edit3.Text:=FloatToStr(s);
end;

end.