delphi: binary sort
 

Posted by bryn.

Student on team #1 from uni.

Posted on 11/23/2000 6:00 AM MST



hi, this is the code in my prog.
basically it reads a file called list.txt
and then finds a number which the user entered... prob is it only works for sorted data. and i need to get a sort going! a binary sort would be good!
how do i do it? could someone sort it for me?
and email it, its kinda important heh
brynbush@hotmail.com
cheers
Bryn

unit Unit1;

interface

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

type
TForm1 = class(TForm)
Findbtn: TButton;
Inputbox: TEdit;
Label1: TLabel;
Label2: TLabel;
DispBox: TMemo;
outputbox: TMemo;
Label3: TLabel;
Label4: TLabel;
procedure FindbtnClick(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.FindbtnClick(Sender: TObject);
var fil:textfile;
nam:Array [1..40] of string;
num:Array [1..40] of integer;
ct:integer;
items:integer;
high:integer;
Mid:integer;
Low:integer;
Number:integer;
begin
Assignfile(fil,'c:\delphi\soft124\list.txt');
Reset(Fil);
ct:=0;
while not(eof(fil)) do
begin
ct:=ct+1;
Readln(fil, num [ct], nam [ct]);
DispBox.Lines.Add(Format('%2d %4d %s', [ct, num[ct], nam[ct]]));
end;
items := ct;
outputbox.clear;
Number := strtoint(inputbox.text);

low := 1;
high := items;

Inputbox.clear;
if Number = num[low] then
Outputbox.Lines.Add(format('%3d %s', [low,nam[low]]));
if Number num[high] then
showmessage('Number Entered is too High')
else
if Number = num[high] then
Outputbox.Lines.Add(format('%3d %s', [high,nam[high]]))
else
repeat
mid := trunc((low+high)/2);
if Number = num[mid] then
Outputbox.Lines.Add(format('%3d %s', [Mid,nam[Mid]]))
else
if Number