برامج وتقنيات: استعمال آوامر الحلقات for و while

تستعمل الصيغتين while و For لتكرر أمر معين حتى يتحقق شرط أو شروط معينة ، وهذه أمثلة عن استعمالاتهما :


unit Unit1;

interface

uses
  System.SysUtils, System.Types, System.UITypes, System.Classes,
  System.Variants,
  FMX.Types, FMX.Controls, FMX.Forms, FMX.Graphics, FMX.Dialogs, FMX.StdCtrls,
  FMX.Layouts, FMX.Memo, FMX.Controls.Presentation, FMX.ScrollBox;

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    Button4: TButton;
    Button5: TButton;
    Memo1: TMemo;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
    procedure Button5Click(Sender: TObject);
  private
    { Déclarations privées }
  public
    { Déclarations publiques }
    procedure Show(const msg: string);
  end;

var
  Form1: TForm1;

implementation

{$R *.fmx}
{ TForm1 }

uses
  System.Diagnostics;

procedure TForm1.Button1Click(Sender: TObject);
var
  I: Integer;
begin
  for I := 1 to 20 do
    Show('Number ' + IntToStr(I));
end;

procedure TForm1.Button2Click(Sender: TObject);
var
  I: Integer;
begin
  I := 1;
  while I <= 20 do
  begin
    Show('Number ' + IntToStr(I));
    Inc(I, 2)
  end;

end;

procedure TForm1.Button3Click(Sender: TObject);
var
  I: Integer;
begin
  Randomize;
  I := 1;
  while I < 500 do
  begin
    Show('Random Number: ' + IntToStr(I));
    I := I + Random(100);
  end;

end;

procedure TForm1.Button4Click(Sender: TObject);
var
  s: string;
  ch: Char;
begin
  s := 'Hello world';
  for ch in s do
    Show(ch);

end;

procedure TForm1.Button5Click(Sender: TObject);
var
  s: string;
  I: Integer;
  Total: Integer;
  SW: TStopWatch;
  ch: Char;
begin
  // create a thirty million char string
  s := '';
  for I := 1 to 30000000 do
  begin
    // take the first char of the number
    s := s + IntToStr(I).Chars[1];
  end;

  SW := TStopWatch.StartNew;
  Total := 0;
  for I := Low(s) to High(s) do
  begin
    Total := Total + Ord(s[I]);
  end;
  SW.Stop;
  Show('for ' + Total.ToString + ' [' + SW.ElapsedMilliseconds.ToString + '] ');

  SW := TStopWatch.StartNew;
  Total := 0;
  for ch in s do
  begin
    Total := Total + Ord(ch);
  end;
  SW.Stop;
  Show('for ' + Total.ToString + ' [' + SW.ElapsedMilliseconds.ToString + '] ');

end;

procedure TForm1.Show(const msg: string);
begin
  Memo1.Lines.Add(msg);
end;

end.
//********************************************

برامج وتقنيات

الصفحات

استعمال آوامر الحلقات for و while

المشاركات الشائعة