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动态数组直接 := 赋值给新数组,那么这2个数组还是同一个数组,修改任意一个数组成员值,另外一个数组也跟随着变化。
如果动态数组用Copy赋值,那么则不会跟着随动变化
代码如下:
unit Unit1; interface uses Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics, Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls; type TForm1 = class(TForm) Memo1: TMemo; Button1: TButton; procedure Button1Click(Sender: TObject); private { Private declarations } public { Public declarations } end; var Form1: TForm1; implementation {$R *.dfm} uses System.Diagnostics, System.Math; type TDays = array of Integer; //函数定义 procedure ShowStaticArrays(); var m_Day: TDays; m_Day1, m_Day2: TDays; I: Integer; begin SetLength(m_Day, 3); for I := Low(m_Day) to High(m_Day) do begin m_Day[I] := I; end; m_Day1 := m_Day; // 会修改原数组结果 m_Day2 := Copy(m_Day, Low(m_Day), Length(m_Day));// 不会修改原数组结果 m_Day1[1] := 520; m_Day2[2] := 3344; for I := Low(m_Day) to High(m_Day) do begin Form1.Memo1.Lines.Add(‘m_Day[‘ + I.ToString + ‘] := ‘ + m_Day[I].ToString); end; for I := Low(m_Day) to High(m_Day) do begin Form1.Memo1.Lines.Add(‘m_Day1 [‘ + I.ToString + ‘] := ‘ + m_Day1[I].ToString); end; for I := Low(m_Day) to High(m_Day) do begin Form1.Memo1.Lines.Add(‘m_Day2 [‘ + I.ToString + ‘] := ‘ + m_Day2[I].ToString); end; end; //计时 procedure TForm1.Button1Click(Sender: TObject); begin ShowStaticArrays(); end; end.
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原文地址:http://www.cnblogs.com/GodPan/p/4908144.html