unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    txtweight: TEdit;
    txtdistence: TEdit;
    txtprice: TEdit;
    resultstr: TButton;
    //procedure TForm1(Sender: TObject);
    procedure resultstrClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.resultstrClick(Sender: TObject);
var p,w,d,f:real;  s:integer;
begin
  w:=strtofloat(txtweight.Text);  //货物重量赋值w
  s:=strtoint(txtdistence.Text);    //运输距离赋给s
  p:=strtofloat(txtprice.Text);     //基本费用赋给p
  case s of
    0..249:   d:=0;
    250..499:   d:=0.02;
    500..999:    d:=0.05;
    1000..1999:  d:=0.08;
    2000..2999:   d:=0.1;
  else
    d:=0.15;
  end;
  f:=p*w*s*(1-d);
  resultstr.Caption :='运费为'+floattostr(f)
  
end;

end.