动态数组的复制

最近动态数组用的较多，顺便收集了动态数组复制的方法（源自万一的博客）：

unit Unit1;interfaceuses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls;type TForm1 = class(TForm) Button1: TButton; procedure FormCreate(Sender: TObject); procedure Button1Click(Sender: TObject); end;var Form1: TForm1;implementation{$R *.dfm}type TArr = array of Int64; {先把需要的动态数组数组定义成一个类型, 因为下面需要类型转换}var arr1,arr2: TArr; {两个等待测试的数组变量} p: Pointer; {该指针用于中转数组中的数据}{先给第一个数组赋测试值}procedure TForm1.FormCreate(Sender: TObject);var i: Integer;begin for i := 0 to 1000 - 1 do begin SetLength(arr1, Length(arr1)+1); arr1[High(arr1)] := i * 2; end; {抽查显示} ShowMessage(IntToStr(arr1[9])); {18}end;{复制到第二个数组}procedure TForm1.Button1Click(Sender: TObject);var size: Cardinal;begin size := Length(arr1) * SizeOf(arr1[0]); {源数组大小} GetMem(p, size); {根据源数组大小分配内存} CopyMemory(p, arr1, size); {复制} arr2 := TArr(p); {转换} {抽查显示} ShowMessage(IntToStr(arr2[9])); {18}end;end.

结构数组：

unit Unit1;interfaceuses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls;type TForm1 = class(TForm) Button1: TButton; procedure FormCreate(Sender: TObject); procedure Button1Click(Sender: TObject); end;var Form1: TForm1;implementation{$R *.dfm}type TRec = record str: string; int: Integer; end; TArr = array of TRec;var arr1,arr2: TArr; p: Pointer;procedure TForm1.FormCreate(Sender: TObject);var i: Integer;begin for i := 0 to 1000 - 1 do begin SetLength(arr1, Length(arr1)+1); arr1[High(arr1)].str := IntToStr(i); arr1[High(arr1)].int := i * 2; end; ShowMessageFmt('%s,%d',[arr1[9].str, arr1[9].int]); {9,18}end;procedure TForm1.Button1Click(Sender: TObject);var size: Cardinal;begin size := Length(arr1) * SizeOf(arr1[0]); GetMem(p, size); CopyMemory(p, arr1, size); arr2 := TArr(p); ShowMessageFmt('%s,%d',[arr2[9].str, arr2[9].int]); {9,18}end;end.