Created
October 5, 2011 14:35
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Quicksort algorithm in Pascal
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program quicksort; | |
{$mode objfpc}{$H+} | |
uses | |
{$IFDEF UNIX}{$IFDEF UseCThreads} | |
cthreads, | |
{$ENDIF}{$ENDIF} | |
Classes, windows; | |
{$R *.res} | |
type tNameArray = array of string; | |
procedure quickSortArray(var inputArray : tNameArray; lowPos, highPos : integer); | |
//This is a recursive quicksort that cuts the array down into smaller parts to be sorted each pass | |
var | |
movablePointer, immovablePointer, temporaryPointer : integer; | |
temporaryItem : string; | |
begin | |
immovablePointer := lowPos; //Set the immovable pointer to the lowest input part of the array | |
movablePointer := highPos; //Set the movable pointer to the highest input part of the array | |
while (movablePointer <> immovablePointer) do | |
begin | |
if(movablePointer > immovablePointer) then | |
//While the movable pointer is larger than the immovable, slowly move it towards the immovable, checking each step if | |
//the value at that position is larger than the immovable's position. | |
begin | |
if(inputArray[movablePointer] < inputArray[immovablePointer]) then //If they are in the wrong order, swap them! | |
begin | |
temporaryItem := inputArray[movablePointer]; //Exchange the values in the array with a temporary value | |
inputArray[movablePointer] := inputArray[immovablePointer]; | |
inputArray[immovablePointer] := temporaryItem; | |
temporaryPointer := movablePointer; //Exchange the positions to check | |
movablePointer := immovablePointer; | |
immovablePointer := temporaryPointer; | |
end | |
else | |
begin | |
dec(movablePointer); //Otherwise move the movable clsoer to the immovable | |
end; | |
end | |
else | |
begin | |
//Similar as above, but in the other direction | |
if(inputArray[movablePointer] > inputArray[immovablePointer]) then | |
begin | |
temporaryItem := inputArray[movablePointer]; | |
inputArray[movablePointer] := inputArray[immovablePointer]; | |
inputArray[immovablePointer] := temporaryItem; | |
temporaryPointer := movablePointer; | |
movablePointer := immovablePointer; | |
immovablePointer := temporaryPointer; | |
end | |
else | |
begin | |
inc(movablePointer); | |
end; | |
end; | |
//windows.beep(movablePointer * 40,20); | |
end; | |
//Now recursively check the lower and higher up parts of the array to sort | |
if(movablePointer > lowPos) then | |
quickSortArray(inputArray,lowPos,movablePointer-1); | |
if(movablePointer < highPos) then | |
quickSortArray(inputArray,movablePointer+1,highPos); | |
end; | |
var | |
nameArray : tNameArray; | |
count : integer; | |
begin | |
setLength(nameArray,100); | |
nameArray[0] := 'chris'; | |
nameArray[1] := 'bob'; | |
nameArray[2] := 'anna'; | |
nameArray[3] := 'max'; | |
nameArray[4] := 'tom'; | |
nameArray[5] := 'fran'; | |
nameArray[6] := 'michael'; | |
nameArray[7] := 'john'; | |
nameArray[8] := 'alex'; | |
nameArray[9] := 'kirsty'; | |
for count := 0 to high(nameArray) do | |
begin | |
nameArray[count] := char(round(random*20)); | |
end; | |
quickSortArray(nameArray,low(nameArray),high(nameArray)); | |
for count := 0 to high(nameArray) do | |
begin | |
writeln(nameArray[count]); | |
end; | |
readln; | |
end. |
:P very nice such quick much sort so wow
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The best recursive quicksort made in pascal that i have ever found. Good job and thank you!