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.