学步园

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    Button4: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);

  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

{对字符数组, 全部转换}
procedure TForm1.Button1Click(Sender: TObject);
var
  buf: array[0..6] of Char;
begin
  buf := 'ABCDEFG';
  CharLowerBuff(buf, Length(buf));

  ShowMessage(buf); {abcdefg}
end;

{只转换前 3}
procedure TForm1.Button2Click(Sender: TObject);
var
  buf: array[0..6] of Char;
begin
  buf := 'ABCDEFG';
  CharLowerBuff(buf, 3);

  ShowMessage(buf); {abcDEFG}
end;

{返回值}
procedure TForm1.Button3Click(Sender: TObject);
var
  buf: array[0..6] of Char;
  num: Integer;
begin
  buf := 'ABCDEFG';
  num := CharLowerBuff(buf, 4);

  ShowMessageFmt('%s, %d', [string(buf), num]); {abcdEFG, 4}
end;

{对字符串}
procedure TForm1.Button4Click(Sender: TObject);
var
  str: string;
begin
  str := 'ABCDEFG';
  CharLowerBuff(@str[1], Length(str));
  ShowMessage(str); {abcdefg}
end;

end.