delphi dynamic Array 排序快速排序,选择排序,冒泡排序

{

这段代码存在的目的不是在研究这3个排序的算法，

这段代码存在的目的是如何用这3个排序函数，并且选出一个排序速度最快的函数面对实际应用

}

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    Memo1: TMemo;
    Button1: TButton;
    Button2: TButton;
    Memo2: TMemo;
    Edit1: TEdit;
    Label1: TLabel;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

{选择排序}
procedure selectrank(var a:array of integer;maxtomin:boolean);
var i,j,t:integer;
begin
   if maxtomin then                 //由大到小
     begin
       for i:=low(a) to high(a)-1 do
         for j:=i+1 to high(a) do
             if a[i]<a[j] then
                begin
                   t:=a[i];
                   a[i]:=a[j];
                   a[j]:=t;
                end;
     end
   else                     //由小到大
    begin
     for i:=low(a) to high(a)-1 do
         for j:=i+1 to high(a) do
             if a[i]>a[j] then    //关键区别是符号
                begin
                   t:=a[i];
                   a[i]:=a[j];
                   a[j]:=t;
                end;
     end;
end;

{快速排序}
procedure speedrank(var a:array of integer;maxtomin:boolean);
var i,j,t:integer;
    flag:boolean;
begin
  if maxtomin then                  //由大到小
     begin
        i:=1;
        repeat
          flag:=true;
          for j:=low(a) to high(a)-i do
             if a[j]<a[j+1] then
                begin
                   t:=a[j];
                   a[j]:=a[j+1];
                   a[j+1]:=t;
                   flag:=false;
                end;
           i:=i+1;
        until flag;
     end//end if
  else                        //由小到大
    begin
      i:=1;
      repeat
         flag:=true;
         for j:=low(a) to high(a)-i do
            if a[j]>a[j+1] then   //关键点是大于好还是小于号
               begin
               t:=a[j];
               a[j]:=a[j+1];
               a[j+1]:=t;
               flag:=false;
               end;
               i:=i+1;
      until flag;
    end;
end;

{冒泡排序法}
procedure bublerank(var a:array of integer;maxtomin:boolean);
var i,j,t:integer;
begin
  if maxtomin then             //由大到校排序
    begin
      for i:=low(a) to high(a)-1 do
          for j:=low(a) to high(a)-i-1 do
                  if a[j]<a[j+1] then
                     begin
                       t:=a[j];
                       a[j]:=a[j+1];
                       a[j+1]:=t;
                     end;
    end
  else                         //由小到大排序
   begin
    for i:=low(a) to high(a)-1 do
        for j:=low(a) to high(a)-i-1 do
                if a[j]>a[j+1] then
                   begin
                     t:=a[j];
                     a[j]:=a[j+1];
                     a[j+1]:=t;
                   end;
   end;
end;

var A:  Array of Integer;{共有部分}
{1/2产生13个随机数组}
procedure TForm1.Button1Click(Sender: TObject);
var  i:integer;{1/2产生随机数并给数组赋值}
begin
   Memo1.Clear;
  SetLength(A,StrToInt(Edit1.Text));//动态数组的长度
  for i:=Low(A) to High(A) do
   begin
      Randomize;
      a[i]:=Random(100);
      Memo1.Lines.Add(IntToStr(a[i]));{}
   end;
end;

{2/2排序}
procedure TForm1.Button2Click(Sender: TObject);
var  i:integer; {2/2重小到大排序->取最小值}
begin
  Memo2.Clear; //
  for i:=Low(A) to High(A) do
   begin
      speedrank(a,False); {排序}
      Memo2.Lines.Add(Format('%d',[a[i]])); {显示结果}
   end;
   if A<>nil then  Button2.caption:=Format('min=%d',[a[0]]);{取出最小值:从小到大排序的最终结果最小值就是第1位}
   A:=nil;{排完序后立即释放动态数组}
end;

end.

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delphi dynamic Array 排序 快速排序,选择排序,冒泡排序

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delphi dynamic Array 排序快速排序,选择排序,冒泡排序