WinAPI 字符及字符串函数(13): lstrcmp、lstrcmpi - 对比串

lstrcmp 区分大小写; lstrcmpi 不区分大小写. 返回值: -1、0、1, 其中 0 表示相同.

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;
    Button5: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
    procedure Button5Click(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

const
  Msgs: array[-1..1] of Char = ('<', '=', '>');

procedure TForm1.Button1Click(Sender: TObject);
var
  p1,p2: PChar;
  n: Integer;
begin
  p1 := 'A';
  p2 := 'B';

  n := lstrcmp(p1, p2);
  ShowMessageFmt('%s %s %s', [p1, Msgs[n], p2]); {A < B}

  n := lstrcmpi(p1, p2);
  ShowMessageFmt('%s %s %s', [p1, Msgs[n], p2]); {A < B}
end;

procedure TForm1.Button2Click(Sender: TObject);
var
  p1,p2: PChar;
  n: Integer;
begin
  p1 := 'A';
  p2 := 'a';

  n := lstrcmp(p1, p2);
  ShowMessageFmt('%s %s %s', [p1, Msgs[n], p2]); {A > a}

  n := lstrcmpi(p1, p2);
  ShowMessageFmt('%s %s %s', [p1, Msgs[n], p2]); {A = a}
end;

procedure TForm1.Button3Click(Sender: TObject);
var
  p1,p2: PChar;
  n: Integer;
begin
  p1 := 'ABC';
  p2 := 'abcd';

  n := lstrcmp(p1, p2);
  ShowMessageFmt('%s %s %s', [p1, Msgs[n], p2]); {ABC < abcd}

  n := lstrcmpi(p1, p2);
  ShowMessageFmt('%s %s %s', [p1, Msgs[n], p2]); {ABC < abcd}
end;

{这和 Delphi 的 CompareStr、CompareText 区别还是很大}
procedure TForm1.Button4Click(Sender: TObject);
var
  p1,p2: PChar;
  n: Integer;
begin
  p1 := 'A';
  p2 := 'a';

  n := CompareStr(p1, p2);
  ShowMessage(IntToStr(n)); {-32}

  n := CompareText(p1, p2);
  ShowMessage(IntToStr(n)); {0}
end;

{和 StrComp、StrIComp、StrLComp、StrLIComp 也不一样}
procedure TForm1.Button5Click(Sender: TObject);
var
  p1,p2: PChar;
  n: Integer;
begin
  p1 := 'A';
  p2 := 'a';

  n := StrComp(p1, p2);
  ShowMessage(IntToStr(n)); {-32}

  n := StrIComp(p1, p2);
  ShowMessage(IntToStr(n)); {0}

  n := StrLComp(p1, p2, 1);
  ShowMessage(IntToStr(n)); {-32}

  n := StrLIComp(p1, p2, 1);
  ShowMessage(IntToStr(n)); {0}
end;

end.