使用泛型的 TArray 从动态数组中查找指定元素

unit Unit1;



interface



uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, StdCtrls;



type

  TForm1 = class(TForm)

    Button1: TButton;

    Button2: TButton;

    procedure Button1Click(Sender: TObject);

    procedure Button2Click(Sender: TObject);

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



uses Generics.Collections; {引用泛型单元}



{从字符串数组中查找}

procedure TForm1.Button1Click(Sender: TObject);

var

  arr: array of string;

  num: Integer;

begin

  {构建动态数组}

  SetLength(arr, 5);

  arr[0] := 'aaa';

  arr[1] := 'bbb';

  arr[2] := 'ccc';

  arr[3] := 'ddd';

  arr[4] := 'eee';



  {查找}

  TArray.BinarySearch<string>(arr, 'ddd', num);



  {显示查找结果}

  if num < Length(arr) then {如果 num = Length(arr) 就是没找到}

    ShowMessage(IntToStr(num)); {3}

end;



{从整数数组中查找}

procedure TForm1.Button2Click(Sender: TObject);

var

  arr: array of Integer;

  num: Integer;

begin

  {构建动态数组}

  SetLength(arr, 5);

  arr[0] := 11;

  arr[1] := 22;

  arr[2] := 33;

  arr[3] := 44;

  arr[4] := 55;



  {查找}

  TArray.BinarySearch<Integer>(arr, 44, num);



  {显示查找结果}

  if num < Length(arr) then {如果 num = Length(arr) 就是没找到}

    ShowMessage(IntToStr(num)); {3}

end;



end.