# Sorting algorithms/Comb sort

(Redirected from Comb sort)
This task has been clarified. Its programming examples are in need of review to ensure that they still fit the requirements of the task.
Sorting algorithms/Comb sort
You are encouraged to solve this task according to the task description, using any language you may know.

Sorting Algorithm
This is a sorting algorithm. It may be applied to a set of data in order to sort it.

For other sorting algorithms, see Category:Sorting Algorithms, or:
O(n logn) Sorts
Heapsort | Mergesort | Quicksort
O(n log2n) Sorts
Shell Sort
O(n2) Sorts
Bubble sort | Cocktail sort | Comb sort | Gnome sort | Insertion sort | Selection sort | Strand sort
Other Sorts
Bead sort | Bogosort | Counting sort | Pancake sort | Permutation sort | Radix sort | Sleep sort | Stooge sort

Implement a   comb sort.

The Comb Sort is a variant of the Bubble Sort.

Like the Shell sort, the Comb Sort increases the gap used in comparisons and exchanges.

Dividing the gap by   ${\displaystyle (1-e^{-\varphi })^{-1}\approx 1.247330950103979}$   works best, but   1.3   may be more practical.

Some implementations use the insertion sort once the gap is less than a certain amount.

Also see

Variants:

• Combsort11 makes sure the gap ends in (11, 8, 6, 4, 3, 2, 1), which is significantly faster than the other two possible endings.
• Combsort with different endings changes to a more efficient sort when the data is almost sorted (when the gap is small).   Comb sort with a low gap isn't much better than the Bubble Sort.

Pseudocode:

function combsort(array input)
gap := input.size //initialize gap size
loop until gap = 1 and swaps = 0
//update the gap value for a next comb. Below is an example
gap := int(gap / 1.25)
if gap < 1
//minimum gap is 1
gap := 1
end if
i := 0
swaps := 0 //see Bubble Sort for an explanation
//a single "comb" over the input list
loop until i + gap >= input.size //see Shell sort for similar idea
if input[i] > input[i+gap]
swap(input[i], input[i+gap])
swaps := 1 // Flag a swap has occurred, so the
// list is not guaranteed sorted
end if
i := i + 1
end loop
end loop
end function

## 360 Assembly

Translation from prototype.
The program uses ASM structured macros and two ASSIST macros to keep the code as short as possible.

*        Comb sort                 23/06/2016
COMBSORT CSECT
USING COMBSORT,R13 base register
B 72(R15) skip savearea
DC 17F'0' savearea
STM R14,R12,12(R13) prolog
ST R13,4(R15) "
ST R15,8(R13) "
LR R13,R15 "
L R2,N n
BCTR R2,0 n-1
ST R2,GAP gap=n-1
DO UNTIL=(CLC,GAP,EQ,=F'1',AND,CLI,SWAPS,EQ,X'00') repeat
L R4,GAP gap |
MH R4,=H'100' gap*100 |
SRDA R4,32 . |
D R4,=F'125' /125 |
ST R5,GAP gap=int(gap/1.25) |
IF CLC,GAP,LT,=F'1' if gap<1 then -----------+ |
MVC GAP,=F'1' gap=1 | |
ENDIF , end if <-----------------+ |
MVI SWAPS,X'00' swaps=false |
LA RI,1 i=1 |
DO UNTIL=(C,R3,GT,N) do i=1 by 1 until i+gap>n ---+ |
LR R7,RI i | |
SLA R7,2 . | |
LA R7,A-4(R7) [email protected](i) | |
LR R8,RI i | |
A R8,GAP i+gap | |
SLA R8,2 . | |
LA R8,A-4(R8) [email protected](i+gap) | |
L R2,0(R7) temp=a(i) | |
IF C,R2,GT,0(R8) if a(i)>a(i+gap) then ---+ | |
MVC 0(4,R7),0(R8) a(i)=a(i+gap) | | |
ST R2,0(R8) a(i+gap)=temp | | |
MVI SWAPS,X'01' swaps=true | | |
ENDIF , end if <-----------------+ | |
LA RI,1(RI) i=i+1 | |
LR R3,RI i | |
A R3,GAP i+gap | |
ENDDO , end do <---------------------+ |
ENDDO , until gap=1 and not swaps <------+
LA R3,PG pgi=0
LA RI,1 i=1
DO WHILE=(C,RI,LE,N) do i=1 to n -------+
LR R1,RI i |
SLA R1,2 . |
L R2,A-4(R1) a(i) |
XDECO R2,XDEC edit a(i) |
MVC 0(4,R3),XDEC+8 output a(i) |
LA R3,4(R3) pgi=pgi+4 |
LA RI,1(RI) i=i+1 |
ENDDO , end do <-----------+
XPRNT PG,L'PG print buffer
L R13,4(0,R13) epilog
LM R14,R12,12(R13) "
XR R15,R15 "
BR R14 exit
A DC F'4',F'65',F'2',F'-31',F'0',F'99',F'2',F'83',F'782',F'1'
DC F'45',F'82',F'69',F'82',F'104',F'58',F'88',F'112',F'89',F'74'
N DC A((N-A)/L'A) number of items of a
GAP DS F gap
SWAPS DS X flag for swaps
PG DS CL80 output buffer
XDEC DS CL12 temp for edit
YREGS
RI EQU 6 i
END COMBSORT
Output:
-31   0   1   2   2   4  45  58  65  69  74  82  82  83  88  89  99 104 112 782

## ActionScript

function combSort(input:Array)
{
var gap:uint = input.length;
var swapped:Boolean = false;
while(gap > 1 || swapped)
{
gap /= 1.25;
swapped = false;
for(var i:uint = 0; i + gap < input.length; i++)
{
if(input[i] > input[i+gap])
{
var tmp = input[i];
input[i] = input[i+gap];
input[i+gap]=tmp;
swapped = true;
}
}
}
return input;
}

procedure Comb_Sort is
generic
type Element_Type is private;
type Index_Type is range <>;
type Array_Type is array (Index_Type range <>) of Element_Type;
with function ">" (Left, Right : Element_Type) return Boolean is <>;
with function "+" (Left : Index_Type; Right : Natural) return Index_Type is <>;
with function "-" (Left : Index_Type; Right : Natural) return Index_Type is <>;
procedure Comb_Sort (Data: in out Array_Type);

procedure Comb_Sort (Data: in out Array_Type) is
procedure Swap (Left, Right : in Index_Type) is
Temp : Element_Type := Data(Left);
begin
Data(Left)  := Data(Right);
Data(Right) := Temp;
end Swap;
Gap : Natural := Data'Length;
Swap_Occured : Boolean;
begin
loop
Gap := Natural (Float(Gap) / 1.25 - 0.5);
if Gap < 1 then
Gap := 1;
end if;
Swap_Occured := False;
for I in Data'First .. Data'Last - Gap loop
if Data (I) > Data (I+Gap) then
Swap (I, I+Gap);
Swap_Occured := True;
end if;
end loop;
exit when Gap = 1 and not Swap_Occured;
end loop;
end Comb_Sort;

type Integer_Array is array (Positive range <>) of Integer;
procedure Int_Comb_Sort is new Comb_Sort (Integer, Positive, Integer_Array);
Test_Array : Integer_Array := (1, 3, 256, 0, 3, 4, -1);
begin
Int_Comb_Sort (Test_Array);
for I in Test_Array'Range loop
end loop;
end Comb_Sort;

Output:

-1 0 1 3 3 4 256

## AutoHotkey

List1 = 23,76,99,58,97,57,35,89,51,38,95,92,24,46,31,24,14,12,57,78
List2 = 88,18,31,44,4,0,8,81,14,78,20,76,84,33,73,75,82,5,62,70

List2Array(List1, "MyArray")
CombSort("MyArray")
MsgBox, % List1 "n" Array2List("MyArray")

List2Array(List2, "MyArray")
CombSort("MyArray")
MsgBox, % List2 "n" Array2List("MyArray")

;---------------------------------------------------------------------------
CombSort(Array) { ; CombSort of Array %Array%, length = %Array%0
;---------------------------------------------------------------------------
Gap := %Array%0
While Gap > 1 Or Swaps {
If (Gap > 1)
Gap := 4 * Gap // 5
i := Swaps := False
While (j := ++i + Gap) <= %Array%0 {
If (%Array%%i% > %Array%%j%) {
Swaps := True
%Array%%i% := (%Array%%j% "", %Array%%j% := %Array%%i%)
}
}
}
}

;---------------------------------------------------------------------------
List2Array(List, Array) { ; creates an array from a comma separated list
;---------------------------------------------------------------------------
global
StringSplit, %Array%, List, `,
}

;---------------------------------------------------------------------------
Array2List(Array) { ; returns a comma separated list from an array
;---------------------------------------------------------------------------
Loop, % %Array%0
List .= (A_Index = 1 ? "" : ",") %Array%%A_Index%
Return, List
}

Message (1) box shows:

23,76,99,58,97,57,35,89,51,38,95,92,24,46,31,24,14,12,57,78
12,14,23,24,24,31,35,38,46,51,57,57,58,76,78,89,92,95,97,99

Message (2) box shows:

88,18,31,44,4,0,8,81,14,78,20,76,84,33,73,75,82,5,62,70
0,4,5,8,14,18,20,31,33,44,62,70,73,75,76,78,81,82,84,88

## AWK

function combsort( a, len,    gap, igap, swap, swaps, i )
{
gap = len
swaps = 1

while( gap > 1 || swaps )
{
gap /= 1.2473;
if ( gap < 1 ) gap = 1
i = swaps = 0
while( i + gap < len )
{
igap = i + int(gap)
if ( a[i] > a[igap] )
{
swap = a[i]
a[i] = a[igap]
a[igap] = swap
swaps = 1
}
i++;
}
}
}

BEGIN {
a[0] = 5
a[1] = 2
a[2] = 7
a[3] = -11
a[4] = 6
a[5] = 1

combsort( a, length(a) )

for( i=0; i<length(a); i++ )
print a[i]
}

## BBC BASIC

DEF PROC_CombSort11(Size%)

gap%=Size%
REPEAT
IF gap% > 1 THEN
gap%=gap% / 1.3
IF gap%=9 OR gap%=10 gap%=11
ENDIF
I% = 1
Finished%=TRUE
REPEAT
IF data%(I%) > data%(I%+gap%) THEN
SWAP data%(I%),data%(I%+gap%)
Finished% = FALSE
ENDIF
I%+=1
UNTIL I%+gap% > Size%
UNTIL gap%=1 AND Finished%

ENDPROC

## C

Implementation of Combsort11. Its efficiency can be improved by just switching to Insertion sort when the gap size becomes less than 10.

void Combsort11(double a[], int nElements)
{
int i, j, gap, swapped = 1;
double temp;

gap = nElements;
while (gap > 1 || swapped == 1)
{
gap = gap * 10 / 13;
if (gap == 9 || gap == 10) gap = 11;
if (gap < 1) gap = 1;
swapped = 0;
for (i = 0, j = gap; j < nElements; i++, j++)
{
if (a[i] > a[j])
{
temp = a[i];
a[i] = a[j];
a[j] = temp;
swapped = 1;
}
}
}
}

## C++

This is copied from the Wikipedia article.

template<class ForwardIterator>
void combsort ( ForwardIterator first, ForwardIterator last )
{
static const double shrink_factor = 1.247330950103979;
typedef typename std::iterator_traits<ForwardIterator>::difference_type difference_type;
difference_type gap = std::distance(first, last);
bool swaps = true;

while ( (gap > 1) || (swaps == true) ){
if (gap > 1)
gap = static_cast<difference_type>(gap/shrink_factor);

swaps = false;
ForwardIterator itLeft(first);

for ( ; itRight!=last; ++itLeft, ++itRight ){
if ( (*itRight) < (*itLeft) ){
std::iter_swap(itLeft, itRight);
swaps = true;
}
}
}
}

## C#

using System;

namespace CombSort
{
class Program
{
static void Main(string[] args)
{
int[] unsorted = new int[] { 3, 5, 1, 9, 7, 6, 8, 2, 4 };
Console.WriteLine(string.Join(",", combSort(unsorted)));
}
public static int[] combSort(int[] input)
{
double gap = input.Length;
bool swaps = true;
while (gap > 1 || swaps)
{
gap /= 1.247330950103979;
if (gap < 1) { gap = 1; }
int i = 0;
swaps = false;
while (i + gap < input.Length)
{
int igap = i + (int)gap;
if (input[i] > input[igap])
{
int swap = input[i];
input[i] = input[igap];
input[igap] = swap;
swaps = true;
}
i++;
}
}
return input;
}
}
}

## COBOL

This excerpt contains just enough of the procedure division to show the workings. See the example for the bubble sort for a more complete program.

C-PROCESS SECTION.
C-000.
DISPLAY "SORT STARTING".

MOVE WC-SIZE TO WC-GAP.

PERFORM E-COMB UNTIL WC-GAP = 1 AND FINISHED.

DISPLAY "SORT FINISHED".

C-999.
EXIT.

E-COMB SECTION.
E-000.
IF WC-GAP > 1
DIVIDE WC-GAP BY 1.3 GIVING WC-GAP
IF WC-GAP = 9 OR 10
MOVE 11 TO WC-GAP.

MOVE 1 TO WC-SUB-1.
MOVE "Y" TO WF-FINISHED.

PERFORM F-SCAN UNTIL WC-SUB-1 + WC-GAP > WC-SIZE.

E-999.
EXIT.

F-SCAN SECTION.
F-000.
IF WB-ENTRY(WC-SUB-1) > WB-ENTRY(WC-SUB-2)
MOVE WB-ENTRY(WC-SUB-1) TO WC-TEMP
MOVE WB-ENTRY(WC-SUB-2) TO WB-ENTRY(WC-SUB-1)
MOVE WC-TEMP TO WB-ENTRY(WC-SUB-2)
MOVE "N" TO WF-FINISHED.

F-999.
EXIT.

## Common Lisp

(defparameter *shrink* 1.3)

(defun comb-sort (input)
(loop with input-size = (length input)
with gap = input-size
with swapped
do (when (> gap 1)
(setf gap (floor gap *shrink*)))
(setf swapped nil)
(loop for lo from 0
for hi from gap below input-size
when (> (aref input lo) (aref input hi))
do (rotatef (aref input lo) (aref input hi))
(setf swapped t))
while (or (> gap 1) swapped)
finally (return input)))

## D

Translation of: Python
import std.stdio, std.algorithm;

void combSort(T)(T[] input) pure nothrow @safe @nogc {
int gap = input.length;
bool swaps = true;

while (gap > 1 || swaps) {
gap = max(1, cast(int)(gap / 1.2473));
swaps = false;
foreach (immutable i; 0 .. input.length - gap)
if (input[i] > input[i + gap]) {
input[i].swap(input[i + gap]);
swaps = true;
}
}
}

void main() {
auto data = [28, 44, 46, 24, 19, 2, 17, 11, 25, 4];
data.combSort;
data.writeln;
}
Output:
[2, 4, 11, 17, 19, 24, 25, 28, 44, 46]

## Eiffel

class
COMB_SORT [G -> COMPARABLE]

feature

combsort (ar: ARRAY [G]): ARRAY [G]
-- Sorted array in ascending order.
require
array_not_void: ar /= Void
local
gap, i: INTEGER
swap: G
swapped: BOOLEAN
shrink: REAL_64
do
create Result.make_empty
Result.deep_copy (ar)
gap := Result.count
from
until
gap = 1 and swapped = False
loop
from
i := Result.lower
swapped := False
until
i + gap > Result.count
loop
if Result [i] > Result [i + gap] then
swap := Result [i]
Result [i] := Result [i + gap]
Result [i + gap] := swap
swapped := True
end
i := i + 1
end
shrink := gap / 1.3
gap := shrink.floor
if gap < 1 then
gap := 1
end
end
ensure
Result_is_set: Result /= Void
Result_is_sorted: is_sorted (Result)
end

feature {NONE}

is_sorted (ar: ARRAY [G]): BOOLEAN
--- Is 'ar' sorted in ascending order?
require
ar_not_empty: ar.is_empty = False
local
i: INTEGER
do
Result := True
from
i := ar.lower
until
i = ar.upper
loop
if ar [i] > ar [i + 1] then
Result := False
end
i := i + 1
end
end

end

Test:

class
APPLICATION

create
make

feature

make
do
test := <<1, 5, 99, 2, 95, 7, -7>>
io.put_string ("unsorted" + "%N")
across
test as ar
loop
io.put_string (ar.item.out + "%T")
end
io.put_string ("%N" + "sorted:" + "%N")
create combsort
test := combsort.combsort (test)
across
test as ar
loop
io.put_string (ar.item.out + "%T")
end
end

combsort: COMB_SORT [INTEGER]

test: ARRAY [INTEGER]

end

Output:
unsorted:
1 5 99 2 95 7 -7
sorted:
-7 1 2 5 7 95 99

## Elena

ELENA 4.x :

import extensions;
import system'math;
import system'routines;

extension op
{
combSort()
{
var list := self.clone();

real gap := list.Length;
bool swaps := true;
while (gap > 1 || swaps)
{
gap /= 1.247330950103979r;
if (gap<1) { gap := 1 };

int i := 0;
swaps := false;
while (i + gap.RoundedInt < list.Length)
{
int igap := i + gap.RoundedInt;
if (list[i] > list[igap])
{
list.exchange(i,igap);
swaps := true
};
i += 1
}
};

^ list
}
}

public program()
{
var list := new int[]{3, 5, 1, 9, 7, 6, 8, 2, 4 };

console.printLine("before:", list.asEnumerable());
console.printLine("after :", list.combSort().asEnumerable())
}
Output:
before:3,5,1,9,7,6,8,2,4
after :1,2,3,4,5,6,7,8,9

## Elixir

defmodule Sort do
def comb_sort([]), do: []
def comb_sort(input) do
comb_sort(List.to_tuple(input), length(input), 0) |> Tuple.to_list
end

defp comb_sort(output, 1, 0), do: output
defp comb_sort(input, gap, _) do
gap = max(trunc(gap / 1.25), 1)
{output,swaps} = Enum.reduce(0..tuple_size(input)-gap-1, {input,0}, fn i,{acc,swap} ->
if (x = elem(acc,i)) > (y = elem(acc,i+gap)) do
{acc |> put_elem(i,y) |> put_elem(i+gap,x), 1}
else
{acc,swap}
end
end)
comb_sort(output, gap, swaps)
end
end

(for _ <- 1..20, do: :rand.uniform(20)) |> IO.inspect |> Sort.comb_sort |> IO.inspect
Output:
[10, 7, 8, 13, 4, 11, 13, 12, 18, 11, 5, 7, 3, 4, 15, 1, 17, 16, 7, 14]
[1, 3, 4, 4, 5, 7, 7, 7, 8, 10, 11, 11, 12, 13, 13, 14, 15, 16, 17, 18]

## Forth

This is an implementation of Comb sort with a different ending. Here Gnome sort is used, since it is rather small. The dataset is rather large, because otherwise the Comb sort routine would never kick in, passing control to Gnome sort almost right away. Note Comb sort can be kept much simpler this way, because Combsort11 optimizations and swapped flags can be discarded.

defer precedes
defer exchange

: gnomesort ( a n)
swap >r 1 ( n c)
begin ( n c)
over over > ( n c f)
while ( n c)
dup if ( n c)
dup dup 1- over over [email protected] precedes
if [email protected] exchange 1- else drop drop 1+ then
else 1+ then ( n c)
repeat drop drop r> drop ( --)
;

: combsort ( a n --)
dup begin ( a n g)
10 13 */ tuck >r >r 0 ( a g 0)
begin ( a g 0)
over [email protected] < ( a g 0 f)
while ( a g 0)
rot >r over over [email protected] precedes ( g 0 f)
if over over [email protected] exchange then ( g 0)
r> rot 1+ rot 1+ ( a g 0)
repeat drop drop r> r> ( a n g)
dup 9 < ( a n g f)
until drop gnomesort ( --)
;

create example
8 93 69 52 50 79 33 52 19 77 , , , , , , , , , ,
72 85 11 61 64 80 64 76 47 65 , , , , , , , , , ,
13 47 23 40 87 45 2 48 22 69 , , , , , , , , , ,
1 53 33 60 57 14 76 32 59 12 , , , , , , , , , ,
74 38 39 22 87 28 37 93 71 88 , , , , , , , , , ,
56 35 48 99 21 35 26 28 58 85 , , , , , , , , , ,
27 16 54 88 82 18 45 64 45 87 , , , , , , , , , ,
98 97 60 77 43 1 64 0 32 89 , , , , , , , , , ,
77 90 68 83 9 76 10 10 95 12 , , , , , , , , , ,
99 23 74 58 54 25 50 9 94 1 , , , , , , , , , ,

:noname >r cells [email protected] + @ swap cells r> + @ swap < ; is precedes
:noname >r cells [email protected] + swap cells r> + over @ over @ swap rot ! swap ! ; is exchange

: .array 100 0 do example i cells + ? loop cr ;

.array example 100 combsort .array

## Fortran

Works with: Fortran version 90 and later
program Combsort_Demo
implicit none

integer, parameter :: num = 20
real :: array(num)

call random_seed
call random_number(array)
write(*,*) "Unsorted array:-"
write(*,*) array
write(*,*)
call combsort(array)
write(*,*) "Sorted array:-"
write(*,*) array

contains

subroutine combsort(a)

real, intent(in out) :: a(:)
real :: temp
integer :: i, gap
logical :: swapped = .true.

gap = size(a)
do while (gap > 1 .or. swapped)
gap = gap / 1.3
if (gap < 1) gap = 1
swapped = .false.
do i = 1, size(a)-gap
if (a(i) > a(i+gap)) then
temp = a(i)
a(i) = a(i+gap)
a(i+gap) = temp;
swapped = .true.
end if
end do
end do

end subroutine combsort

end program Combsort_Demo

## FreeBASIC

' version 21-10-2016
' compile with: fbc -s console
' for boundary checks on array's compile with: fbc -s console -exx

Sub compsort(bs() As Long)
' sort from lower bound to the highter bound
' array's can have subscript range from -2147483648 to +2147483647
Dim As Long lb = LBound(bs)
Dim As Long ub = UBound(bs)
Dim As Long gap = ub - lb
Dim As Long done, i

Do
gap = Int (gap / 1.3)
If gap < 1 Then gap = 1
done = 0
For i = lb To ub - gap
If bs(i) > bs(i + gap) Then
Swap bs(i), bs(i + gap)
done = 1
End If
Next
Loop Until ((gap = 1) And (done = 0))

End Sub

Sub comp11sort(bs() As Long)
' sort from lower bound to the higher bound
' array's can have subscript range from -2147483648 to +2147483647
Dim As Long lb = LBound(bs)
Dim As Long ub = UBound(bs)
Dim As Long gap = ub - lb
Dim As Long done, i

Do
gap = Int(gap / 1.24733)
If gap = 9 Or gap = 10 Then
gap = 11
ElseIf gap < 1 Then
gap = 1
End If
done = 0
For i = lb To ub - gap
If bs(i) > bs(i + gap) Then
Swap bs(i), bs(i + gap)
done = 1
End If
Next
Loop Until ((gap = 1) And (done = 0))

End Sub

' ------=< MAIN >=------

Dim As Long i, array(-7 To 7)

Dim As Long a = LBound(array), b = UBound(array)

Randomize Timer
For i = a To b : array(i) = i  : Next
For i = a To b ' little shuffle
Swap array(i), array(Int(Rnd * (b - a +1)) + a)
Next

Print "normal comb sort"
Print "unsorted ";
For i = a To b : Print Using "####"; array(i); : Next : Print
compsort(array()) ' sort the array
Print " sorted ";
For i = a To b : Print Using "####"; array(i); : Next : Print

Print
Print "comb11 sort"
For i = a To b ' little shuffle
Swap array(i), array(Int(Rnd * (b - a +1)) + a)
Next
Print "unsorted ";
For i = a To b : Print Using "####"; array(i); : Next : Print
comp11sort(array()) ' sort the array
Print " sorted ";
For i = a To b : Print Using "####"; array(i); : Next : Print

' empty keyboard buffer
While Inkey <> "" : Wend
Print : Print "hit any key to end program"
Sleep
End
Output:
normal comb sort
unsorted   -6   5  -1  -3  -7   6   1   7  -4   3   4  -2  -5   0   2
sorted   -7  -6  -5  -4  -3  -2  -1   0   1   2   3   4   5   6   7

comb11 sort
unsorted    4  -7  -1   1   2   3  -3   7   0  -2   6  -5   5  -6  -4
sorted   -7  -6  -5  -4  -3  -2  -1   0   1   2   3   4   5   6   7

## Gambas

Public Sub Main()
Dim siToSort As Short[] = [249, 28, 111, 36, 171, 98, 29, 448, 44, 147, 154, 46, 102, 183, 24,
120, 19, 123, 2, 17, 226, 11, 211, 25, 191, 205, 77]
Dim siStart As Short
Dim siGap As Short = siToSort.Max
Dim bSorting, bGap1 As Boolean

Print "To sort: -"
ShowWorking(siToSort)
Print

Repeat
bSorting = False
siStart = 0
If siGap = 1 Then bGap1 = True

Repeat
If siToSort[siStart] > siToSort[siStart + siGap] Then
Swap siToSort[siStart], siToSort[siStart + siGap]
bSorting = True
End If
Inc siStart
Until siStart + siGap > siToSort.Max

If bSorting Then ShowWorking(siToSort)
siGap /= 1.3
If siGap < 1 Then siGap = 1

Until bSorting = False And bGap1 = True

End
'-----------------------------------------
Public Sub ShowWorking(siToSort As Short[])
Dim siCount As Short

For siCount = 0 To siToSort.Max
Print Str(siToSort[siCount]);
If siCount <> siToSort.Max Then Print ",";
Next

Print

End

Output:

To sort: -
249,28,111,36,171,98,29,448,44,147,154,46,102,183,24,120,19,123,2,17,226,11,211,25,191,205,77

77,28,111,36,171,98,29,448,44,147,154,46,102,183,24,120,19,123,2,17,226,11,211,25,191,205,249
77,11,111,25,171,98,29,448,44,147,154,46,102,183,24,120,19,123,2,17,226,28,211,36,191,205,249
77,11,111,2,17,98,28,211,36,147,154,46,102,183,24,120,19,123,25,171,226,29,448,44,191,205,249
46,11,111,2,17,19,28,25,36,147,29,77,44,183,24,120,98,123,211,171,226,154,448,102,191,205,249
36,11,29,2,17,19,24,25,46,123,111,77,44,154,28,102,98,147,211,171,226,183,448,120,191,205,249
24,11,29,2,17,19,36,25,28,102,98,77,44,154,46,123,111,120,191,171,226,183,448,147,211,205,249
17,11,29,2,24,19,36,25,28,102,46,77,44,120,98,123,111,154,191,147,211,183,249,171,226,205,448
2,11,19,17,24,28,36,25,29,44,46,77,102,111,98,123,120,154,183,147,171,191,205,211,226,249,448
2,11,19,17,24,25,29,28,36,44,46,77,98,111,102,123,120,147,171,154,183,191,205,211,226,249,448
2,11,17,19,24,25,28,29,36,44,46,77,98,102,111,120,123,147,154,171,183,191,205,211,226,249,448

## Go

package main

import "fmt"

func main() {
a := []int{170, 45, 75, -90, -802, 24, 2, 66}
fmt.Println("before:", a)
combSort(a)
fmt.Println("after: ", a)
}

func combSort(a []int) {
if len(a) < 2 {
return
}
for gap := len(a); ; {
if gap > 1 {
gap = gap * 4 / 5
}
swapped := false
for i := 0; ; {
if a[i] > a[i+gap] {
a[i], a[i+gap] = a[i+gap], a[i]
swapped = true
}
i++
if i+gap >= len(a) {
break
}
}
if gap == 1 && !swapped {
break
}
}
}

More generic version that sorts anything that implements sort.Interface:

package main

import (
"sort"
"fmt"
)

func main() {
a := []int{170, 45, 75, -90, -802, 24, 2, 66}
fmt.Println("before:", a)
combSort(sort.IntSlice(a))
fmt.Println("after: ", a)
}

func combSort(a sort.Interface) {
if a.Len() < 2 {
return
}
for gap := a.Len(); ; {
if gap > 1 {
gap = gap * 4 / 5
}
swapped := false
for i := 0; ; {
if a.Less(i+gap, i) {
a.Swap(i, i+gap)
swapped = true
}
i++
if i+gap >= a.Len() {
break
}
}
if gap == 1 && !swapped {
break
}
}
}

## Groovy

Combsort solution:

def makeSwap = { a, i, j -> print "."; a[i] ^= a[j]; a[j] ^= a[i]; a[i] ^= a[j] }

def checkSwap = { a, i, j -> [(a[i] > a[j])].find { it }.each { makeSwap(a, i, j) } }

def combSort = { input ->
def swap = checkSwap.curry(input)
def size = input.size()
def gap = size
def swapped = true
while (gap != 1 || swapped) {
gap = (gap / 1.247330950103979) as int
gap = (gap < 1) ? 1 : gap
swapped = (0..<(size-gap)).any { swap(it, it + gap) }
}
input
}

Combsort11 solution:

def combSort11 = { input ->
def swap = checkSwap.curry(input)
def size = input.size()
def gap = size
def swapped = true
while (gap != 1 || swapped) {
gap = (gap / 1.247330950103979) as int
gap = ((gap < 1) ? 1 : ([10,9].contains(gap) ? 11 : gap))
swapped = (0..<(size-gap)).any { swap(it, it + gap) }
}
input
}

Test:

println   (combSort([23,76,99,58,97,57,35,89,51,38,95,92,24,46,31,24,14,12,57,78,4]))
println (combSort11([23,76,99,58,97,57,35,89,51,38,95,92,24,46,31,24,14,12,57,78,4]))
println ()
println (combSort([88,18,31,44,4,0,8,81,14,78,20,76,84,33,73,75,82,5,62,70,12,7,1]))
println (combSort11([88,18,31,44,4,0,8,81,14,78,20,76,84,33,73,75,82,5,62,70,12,7,1]))

Output:

..................................................................................................................[4, 12, 14, 23, 24, 24, 31, 35, 38, 46, 51, 57, 57, 58, 76, 78, 89, 92, 95, 97, 99]
..........................................................................................................................[4, 12, 14, 23, 24, 24, 31, 35, 38, 46, 51, 57, 57, 58, 76, 78, 89, 92, 95, 97, 99]

...............................................................................................[0, 1, 4, 5, 7, 8, 12, 14, 18, 20, 31, 33, 44, 62, 70, 73, 75, 76, 78, 81, 82, 84, 88]
...............................................................................................[0, 1, 4, 5, 7, 8, 12, 14, 18, 20, 31, 33, 44, 62, 70, 73, 75, 76, 78, 81, 82, 84, 88]

import Data.List
import Control.Arrow

flgInsert x xs = ((x:xs==) &&& id)$insert x xs gapSwapping k = (and *** concat. transpose). unzip . map (foldr (\x (b,xs) -> first (b &&)$ flgInsert x xs) (True,[]))
. transpose. takeWhile (not.null). unfoldr (Just. splitAt k)

combSort xs = (snd. fst) $until (\((b,_),g)-> b && g==1) (\((_,xs),g) ->(gapSwapping g xs, fg g)) ((False,xs), fg$ length xs)
where fg = max 1. truncate. (/1.25). fromIntegral

Example:

*Main> combSort [23,76,99,58,97,57,35,89,51,38,95,92,24,46,31,24,14,12,57,78]
[12,14,23,24,24,31,35,38,46,51,57,57,58,76,78,89,92,95,97,99]

## Io

List do(
combSortInPlace := method(
gap := size
swap := true

while(gap > 1 or swap,
swap = false
gap = (gap / 1.25) floor

for(i, 0, size - gap,
if(at(i) > at(i + gap),
swap = true
swapIndices(i, i + gap)
)
)
)
self)
)

lst := list(23, 76, 99, 58, 97, 57, 35, 89, 51, 38, 95, 92, 24, 46, 31, 24, 14, 12, 57, 78)
lst combSortInPlace println # ==> list(12, 14, 23, 24, 24, 31, 35, 38, 46, 51, 57, 57, 58, 76, 78, 89, 92, 95, 97, 99)

## Icon and Unicon

procedure main()                     #: demonstrate various ways to sort a list and string
demosort(combsort,[3, 14, 1, 5, 9, 2, 6, 3],"qwerty")
end

procedure combsort(X,op) #: return sorted X
local gap,swapped,i

op := sortop(op,X) # select how and what we sort

swappped := gap := *X # initialize gap size and say swapped
until /swapped & gap = 1 do {
gap := integer(gap / 1.25) # update the gap value for a next comb
gap <:= 1 # minimum gap of 1
swapped := &null

i := 0
until (i +:= 1) + gap > *X do # a single "comb" over the input list
if op(X[i+gap],X[i]) then
X[i+1] :=: X[swapped := i] # swap and flag as unsorted
}
return X
end

Note: This example relies on the supporting procedures 'sortop', and 'demosort' in Bubble Sort. The full demosort exercises the named sort of a list with op = "numeric", "string", ">>" (lexically gt, descending),">" (numerically gt, descending), a custom comparator, and also a string.

Abbreviated sample output:
Sorting Demo using procedure combsort
on list : [ 3 14 1 5 9 2 6 3 ]
with op = &null:         [ 1 2 3 3 5 6 9 14 ]   (0 ms)
...
on string : "qwerty"
with op = &null:         "eqrtwy"   (0 ms)

## IS-BASIC

100 PROGRAM "CombSrt.bas"
110 RANDOMIZE
120 NUMERIC ARRAY(11 TO 30)
130 CALL INIT(ARRAY)
140 CALL WRITE(ARRAY)
150 CALL COMBSORT(ARRAY)
160 CALL WRITE(ARRAY)
170 DEF INIT(REF A)
180 FOR I=LBOUND(A) TO UBOUND(A)
190 LET A(I)=RND(98)+1
200 NEXT
210 END DEF
220 DEF WRITE(REF A)
230 FOR I=LBOUND(A) TO UBOUND(A)
240 PRINT A(I);
250 NEXT
260 PRINT
270 END DEF
280 DEF COMBSORT(REF A)
290 LET N,GAP=UBOUND(A):LET SW=1
300 DO WHILE GAP>1 OR SW
310 LET GAP=MAX(INT(GAP/1.3),1):LET SW=0
320 FOR I=LBOUND(A) TO N-GAP
330 IF A(I)>A(I+GAP) THEN
340 LET T=A(I):LET A(I)=A(I+GAP):LET A(I+GAP)=T
350 LET SW=1
360 END IF
370 NEXT
380 LOOP
390 END DEF

## J

Generally, this task should be accomplished in J using /:~. Here we take an approach that's more comparable with the other examples on this page.

Large gap sizes allow some parallelism in comparisons and swaps. (If the gap size is G, then G pairs can be compared and swapped in parallel.) Beyond that, however, the data flow complexity of this algorithm requires a fair bit of micro-management.

combSort=:3 :0
gap=. #y
whilst.1 < gap+swaps do.
swaps=. 0
i=. i.2,gap=. 1 >. <.gap%1.25
while.{:$i=.i #"1~ ({: i) < #y do. swaps=.swaps+#{:k=.i #"1~b=. >/ i{y i=. i+gap y=.((|.k){y) k} y end. end. y ) Example use: combSort 23 76 99 58 97 57 35 89 51 38 95 92 24 46 31 24 14 12 57 78 12 14 23 24 24 31 35 38 46 51 57 57 58 76 78 89 92 95 97 99 combSort 88 18 31 44 4 0 8 81 14 78 20 76 84 33 73 75 82 5 62 70 0 4 5 8 14 18 20 31 33 44 62 70 73 75 76 78 81 82 84 88 ## Java This is copied from the Wikipedia article. public static <E extends Comparable<? super E>> void sort(E[] input) { int gap = input.length; boolean swapped = true; while (gap > 1 || swapped) { if (gap > 1) { gap = (int) (gap / 1.3); } swapped = false; for (int i = 0; i + gap < input.length; i++) { if (input[i].compareTo(input[i + gap]) > 0) { E t = input[i]; input[i] = input[i + gap]; input[i + gap] = t; swapped = true; } } } } ## JavaScript // Node 5.4.1 tested implementation (ES6) function is_array_sorted(arr) { var sorted = true; for (var i = 0; i < arr.length - 1; i++) { if (arr[i] > arr[i + 1]) { sorted = false; break; } } return sorted; } // Array to sort var arr = [4, 9, 0, 3, 1, 5]; var iteration_count = 0; var gap = arr.length - 2; var decrease_factor = 1.25; // Until array is not sorted, repeat iterations while (!is_array_sorted(arr)) { // If not first gap if (iteration_count > 0) // Calculate gap gap = (gap == 1) ? gap : Math.floor(gap / decrease_factor); // Set front and back elements and increment to a gap var front = 0; var back = gap; while (back <= arr.length - 1) { // If elements are not ordered swap them if (arr[front] > arr[back]) { var temp = arr[front]; arr[front] = arr[back]; arr[back] = temp; } // Increment and re-run swapping front += 1; back += 1; } iteration_count += 1; } // Print the sorted array console.log(arr); } Output: [0, 1, 3, 4, 5, 9] ## jq Works with: jq version 1.4 An implementation of the pseudo-code in the task description: # Input should be the array to be sorted. def combsort: # As soon as "condition" is true, emit . and stop: def do_until(condition; next): def u: if condition then . else (next|u) end; u; def swap(i;j): if i==j then . else .[i] as$tmp | .[i] = .[j] | .[j] = $tmp end; . as$in
| length as $length # state: [gap, swaps, array] where: # gap is the gap size; # swaps is a boolean flag indicating a swap has occurred, # implying that the array might not be sorted; # array is the current state of the array being sorted | [$length, false, $in ] | do_until( .[0] == 1 and .[1] == false; # update the gap value for the next "comb": ([1, ((.[0] / 1.25) | floor)] | max) as$gap # minimum gap is 1

# state: [i, swaps, array]
| [0, false, .[2]]
# a single "comb" over the input list:
| do_until( (.[0] + $gap) >=$length;
.[0] as $i | if .[2][$i] > .[2][$i+$gap] then
[$i+1, true, (.[2]|swap($i; $i+$gap))]
else .[0] += 1
end)
| .[0] = $gap ) | .[2] ; ## Julia # v0.6 function combsort!(x::Array)::Array gap, swaps = length(x), true while gap > 1 || swaps gap = floor(Int, gap / 1.25) i, swaps = 0, false while i + gap < length(x) if x[i+1] > x[i+1+gap] x[i+1], x[i+1+gap] = x[i+1+gap], x[i+1] swaps = true end i += 1 end end return x end x = randn(100) @show x combsort!(x) @assert issorted(x) Output: x = [1.41167, 1.19626, 0.821703, 0.336024, -0.708447, 0.694578, 1.49075, -1.07124, -1.59686, -0.720135] combsort!(x) = [-1.59686, -1.07124, -0.720135, -0.708447, 0.336024, 0.694578, 0.821703, 1.19626, 1.41167, 1.49075] ## Kotlin // version 1.1.2 fun <T : Comparable<T>> combSort(input: Array<T>) { var gap = input.size if (gap <= 1) return // already sorted var swaps = false while (gap > 1 || swaps) { gap = (gap / 1.247331).toInt() if (gap < 1) gap = 1 var i = 0 swaps = false while (i + gap < input.size) { if (input[i] > input[i + gap]) { val tmp = input[i] input[i] = input[i + gap] input[i + gap] = tmp swaps = true } i++ } } } fun main(args: Array<String>) { val ia = arrayOf(28, 44, 46, 24, 19, 2, 17, 11, 25, 4) println("Unsorted :${ia.contentToString()}")
combSort(ia)
println("Sorted  : ${ia.contentToString()}") println() val ca = arrayOf('X', 'B', 'E', 'A', 'Z', 'M', 'S', 'L', 'Y', 'C') println("Unsorted :${ca.contentToString()}")
combSort(ca)
println("Sorted  : ${ca.contentToString()}") } Output: Unsorted : [28, 44, 46, 24, 19, 2, 17, 11, 25, 4] Sorted : [2, 4, 11, 17, 19, 24, 25, 28, 44, 46] Unsorted : [X, B, E, A, Z, M, S, L, Y, C] Sorted : [A, B, C, E, L, M, S, X, Y, Z] ## Liberty BASIC 'randomize 0.5 itemCount = 20 dim item(itemCount) for i = 1 to itemCount item(i) = int(rnd(1) * 100) next i print "Before Sort" for i = 1 to itemCount print item(i) next i print: print 't0=time$("ms")

gap=itemCount
while gap>1 or swaps <> 0
gap=int(gap/1.25)
'if gap = 10 or gap = 9 then gap = 11 'uncomment to get Combsort11
if gap <1 then gap = 1
i = 1
swaps = 0
for i = 1 to itemCount-gap
if item(i) > item(i + gap) then
temp = item(i)
item(i) = item(i + gap)
item(i + gap) = temp
swaps = 1
end if
next
wend

print "After Sort"
't1=time$("ms") 'print t1-t0 for i = 1 to itemCount print item(i) next i end ## Lua function combsort(t) local gapd, gap, swaps = 1.2473, #t, 0 while gap + swaps > 1 do local k = 0 swaps = 0 if gap > 1 then gap = math.floor(gap / gapd) end for k = 1, #t - gap do if t[k] > t[k + gap] then t[k], t[k + gap], swaps = t[k + gap], t[k], swaps + 1 end end end return t end print(unpack(combsort{3,5,1,2,7,4,8,3,6,4,1})) ## Maple swap := proc(arr, a, b) local temp; temp := arr[a]: arr[a] := arr[b]: arr[b] := temp: end proc: newGap := proc(gap) local new; new := trunc(gap*10/13); if (new < 1) then return 1; end if; return new; end proc; combsort := proc(arr, len) local gap, swapped,i, temp; swapped := true: gap := len: while ((not gap = 1) or swapped) do gap := newGap(gap): swapped := false: for i from 1 to len-gap by 1 do if (arr[i] > arr[i+gap]) then temp := arr[i]: arr[i] := arr[i+gap]: arr[i+gap] := temp: swapped:= true: end if: end do: end do: end proc: arr := Array([17,3,72,0,36,2,3,8,40,0]); combsort(arr, numelems(arr)); arr; Output: [0,0,2,3,3,8,17,36,40,72] ## Mathematica combSort[list_] := Module[{ gap = 0, listSize = 0, swaps = True}, gap = listSize = Length[list]; While[ !((gap <= 1) && (swaps == False)), gap = [email protected][gap, 1.25]; If[ gap < 1, gap = 1]; i = 1; swaps = False; While[ ! ((i + gap - 1) >= listSize), If[ list[[i]] > list[[i + gap]], swaps = True; list[[i ;; i + gap]] = list[[i + gap ;; i ;; -1]]; ]; i++; ] ] ] [email protected]{2, 1, 3, 7, 6} ->{1, 2, 3, 6, 7} ## MATLAB / Octave function list = combSort(list) listSize = numel(list); gap = int32(listSize); %Coerce gap to an int so we can use the idivide function swaps = true; %Swap flag while not((gap <= 1) && (swaps == false)) gap = idivide(gap,1.25,'floor'); %Int divide, floor the resulting operation if gap < 1 gap = 1; end i = 1; %i equals 1 because all arrays are 1 based in MATLAB swaps = false; %i + gap must be subtracted by 1 because the pseudo-code was writen %for 0 based arrays while not((i + gap - 1) >= listSize) if (list(i) > list(i+gap)) list([i i+gap]) = list([i+gap i]); %swap swaps = true; end i = i + 1; end %while end %while end %combSort Sample Output: >> combSort([4 3 1 5 6 2]) ans = 1 2 3 4 5 6 ## MAXScript fn combSort arr = ( local gap = arr.count local swaps = 1 while not (gap == 1 and swaps == 0) do ( gap = (gap / 1.25) as integer if gap < 1 do ( gap = 1 ) local i = 1 swaps = 0 while not (i + gap > arr.count) do ( if arr[i] > arr[i+gap] do ( swap arr[i] arr[i+gap] swaps = 1 ) i += 1 ) ) return arr ) Output: a = for i in 1 to 10 collect random 1 10 #(2, 6, 5, 9, 10, 7, 2, 6, 1, 4) combsort a #(1, 2, 2, 4, 5, 6, 6, 7, 9, 10) ## NetRexx /* NetRexx */ options replace format comments java crossref savelog symbols binary placesList = [String - "UK London", "US New York" - , "US Boston", "US Washington" - , "UK Washington", "US Birmingham" - , "UK Birmingham", "UK Boston" - ] sortedList = combSort(String[] Arrays.copyOf(placesList, placesList.length)) lists = [placesList, sortedList] loop ln = 0 to lists.length - 1 cl = lists[ln] loop ct = 0 to cl.length - 1 say cl[ct] end ct say end ln return method combSort(input = String[]) public constant binary returns String[] swaps = isTrue gap = input.length loop label comb until gap = 1 & \swaps gap = int gap / 1.25 if gap < 1 then gap = 1 i_ = 0 swaps = isFalse loop label swaps until i_ + gap >= input.length if input[i_].compareTo(input[i_ + gap]) > 0 then do swap = input[i_] input[i_] = input[i_ + gap] input[i_ + gap] = swap swaps = isTrue end i_ = i_ + 1 end swaps end comb return input method isTrue public constant binary returns boolean return 1 == 1 method isFalse public constant binary returns boolean return \isTrue Output UK London US New York US Boston US Washington UK Washington US Birmingham UK Birmingham UK Boston UK Birmingham UK Boston UK London UK Washington US Birmingham US Boston US New York US Washington ## Nim proc combSort[T](a: var openarray[T]) = var gap = a.len var swapped = true while gap > 1 or swapped: gap = gap * 10 div 13 if gap == 9 or gap == 10: gap = 11 if gap < 1: gap = 1 swapped = false var i = 0 for j in gap .. <a.len: if a[i] > a[j]: swap a[i], a[j] swapped = true inc i var a = @[4, 65, 2, -31, 0, 99, 2, 83, 782] combSort a echo a Output: @[-31, 0, 2, 2, 4, 65, 83, 99, 782] ## Objeck bundle Default { class Stooge { function : Main(args : String[]) ~ Nil { nums := [3, 5, 1, 9, 7, 6, 8, 2, 4]; CombSort(nums); each(i : nums) { IO.Console->Print(nums[i])->Print(","); }; IO.Console->PrintLine(); } function : CombSort(input : Int[]) ~ Nil { gap : Float := input->Size(); swaps := true; while(gap > 1 | swaps) { gap /= 1.247330950103979; if(gap < 1) { gap := 1; }; i : Int := 0; swaps := false; while(i + gap < input->Size()) { igap : Int := i + gap->As(Int); if (input[i] > input[igap]) { swap : Int := input[i]; input[i] := input[igap]; input[igap] := swap; swaps := true; }; i += 1; }; }; } } } ## OCaml let comb_sort ~input = let input_length = Array.length input in let gap = ref(input_length) in let swapped = ref true in while (!gap > 1 || !swapped) do if (!gap > 1) then gap := int_of_float (float !gap /. 1.3); swapped := false; for i = 0 to input_length - !gap do if input.(i) > input.(i + !gap) then begin let tmp = input.(i) in input.(i) <- input.(i + !gap); input.(i + !gap) <- tmp; swapped := true; end done done ;; ## Oz declare proc {CombSort Arr} Low = {Array.low Arr} High = {Array.high Arr} Size = High - Low + 1 Gap = {NewCell Size} Swapped = {NewCell true} proc {Swap I J} Arr.J := (Arr.I := Arr.J) end in for while:@Gap>1 orelse @Swapped do if @Gap > 1 then Gap := {Float.toInt {Floor {Int.toFloat @Gap} / 1.3}} end Swapped := false for I in Low..High[email protected]Gap do if Arr.I > Arr.(I[email protected]Gap) then {Swap I I[email protected]Gap} Swapped := true end end end end Arr = {Tuple.toArray unit(3 1 4 1 5 9 2 6 5)} in {CombSort Arr} {Show {Array.toRecord unit Arr}} ## PARI/GP combSort(v)={ my(phi=(1+sqrt(5))/2,magic=1/(1-exp(-phi)),g=#v,swaps); while(g>1 | swaps, if(g>1, g\=magic); swaps=0; for(i=1,#v-g, if(v[i]>v[i+g], my(t=v[i]); v[i]=v[i+g]; v[i+g]=t; swaps++ ) ) ); v }; ## Pascal program CombSortDemo; // NOTE: The array is 1-based // If you want to use this code on a 0-based array, see below type TIntArray = array[1..40] of integer; var data: TIntArray; i: integer; procedure combSort(var a: TIntArray); var i, gap, temp: integer; swapped: boolean; begin gap := length(a); swapped := true; while (gap > 1) or swapped do begin gap := trunc(gap / 1.3); if (gap < 1) then gap := 1; swapped := false; for i := 1 to length(a) - gap do if a[i] > a[i+gap] then begin temp := a[i]; a[i] := a[i+gap]; a[i+gap] := temp; swapped := true; end; end; end; begin Randomize; writeln('The data before sorting:'); for i := low(data) to high(data) do begin data[i] := Random(high(data)); write(data[i]:4); end; writeln; combSort(data); writeln('The data after sorting:'); for i := low(data) to high(data) do begin write(data[i]:4); end; writeln; end. Output: The data before sorting: 10 26 32 10 9 32 38 37 12 9 16 7 25 1 37 7 24 22 7 36 2 5 10 5 33 35 32 18 5 28 7 5 36 12 16 36 24 3 29 15 The data after sorting: 1 2 3 5 5 5 5 7 7 7 7 9 9 10 10 10 12 12 15 16 16 18 22 24 24 25 26 28 29 32 32 32 33 35 36 36 36 37 37 38 program CombSortDemo; // NOTE: The array is 0-based // If you want to use this code on a 1-based array, see above type TIntArray = array[0..39] of integer; var data: TIntArray; i: integer; procedure combSort(var a: TIntArray); var i, gap, temp: integer; swapped: boolean; begin gap := length(a); swapped := true; while (gap > 1) or swapped do begin gap := trunc(gap / 1.3); if (gap < 1) then gap := 1; swapped := false; for i := 0 to length(a) - gap - 1 do if a[i] > a[i+gap] then begin temp := a[i]; a[i] := a[i+gap]; a[i+gap] := temp; swapped := true; end; end; end; begin Randomize; writeln('The data before sorting:'); for i := low(data) to high(data) do begin data[i] := Random(high(data)); write(data[i]:4); end; writeln; combSort(data); writeln('The data after sorting:'); for i := low(data) to high(data) do begin write(data[i]:4); end; writeln; end. ## Perl sub combSort { my @arr = @_; my$gap = @arr;
my $swaps = 1; while ($gap > 1 || $swaps) {$gap /= 1.25 if $gap > 1;$swaps = 0;
foreach my $i (0 ..$#arr - $gap) { if ($arr[$i] >$arr[$i+$gap]) {
@arr[$i,$i+$gap] = @arr[$i+$gap,$i];
$swaps = 1; } } } return @arr; } ## Perl 6 Translation of: Perl sub comb_sort ( @a is copy ) { my$gap = +@a;
my $swaps = 1; while$gap > 1 or $swaps {$gap = ( ($gap * 4) div 5 ) || 1 if$gap > 1;

$swaps = 0; for ^(+@a -$gap) -> $i { my$j = $i +$gap;
if @a[$i] > @a[$j] {
@a[$i,$j] .= reverse;
$swaps = 1; } } } return @a; } my @weights = (^50).map: { 100 + ( 1000.rand.Int / 10 ) }; say @weights.sort.Str eq @weights.&comb_sort.Str ?? 'ok' !! 'not ok'; ## Phix function comb_sort(sequence s) integer gap = length(s)-1 while 1 do gap = max(floor(gap/1.3),1) integer swapped = 0 for i=1 to length(s)-gap do object si = s[i] if si>s[i+gap] then s[i] = s[i+gap] s[i+gap] = si swapped = 1 end if end for if gap=1 and swapped=0 then exit end if end while return s end function ## PHP function combSort($arr){
$gap = count($arr);
$swap = true; while ($gap > 1 || $swap){ if($gap > 1) $gap /= 1.25;$swap = false;
$i = 0; while($i+$gap < count($arr)){
if($arr[$i] > $arr[$i+$gap]){ list($arr[$i],$arr[$i+$gap]) = array($arr[$i+$gap],$arr[$i]);$swap = true;
}
$i++; } } return$arr;
}

## PicoLisp

(de combSort (Lst)
(let (Gap (length Lst) Swaps NIL)
(while (or (> Gap 1) Swaps)
(setq Gap (max 1 (/ (* Gap 4) 5)))
(off Swaps)
(use Lst
(for (G (cdr (nth Lst Gap)) G (cdr G))
(when (> (car Lst) (car G))
(xchg Lst G)
(on Swaps) )
(pop 'Lst) ) ) ) )
Lst )

Output:

: (combSort (88 18 31 44 4 0 8 81 14 78 20 76 84 33 73 75 82 5 62 70))
-> (0 4 5 8 14 18 20 31 33 44 62 70 73 75 76 78 81 82 84 88)

## PL/I

/* From the pseudocode. */
comb_sort: procedure (A);
declare A(*) fixed;
declare t fixed;
declare (i, gap) fixed binary (31);
declare swaps bit (1) aligned;

gap = hbound(A,1) - lbound(A,1); /* initialize the gap size. */
do until (gap <= 1 & swaps);
/* update the gap value for a next comb. */
put skip data (gap);
gap = gap / 1.25e0;
put skip data (gap);
swaps = '1'b;
/* a single "comb" over the array. */
do i = lbound(A,1) by 1 until (i + gap >= hbound(A,1));
if A(i) > A(i+gap) then
do;
t = A(i); A(i) = A(i+gap); A(i+gap) = t;
swaps = '0'b; /* Flag a swap has occurred, so */
/* the list is not guaranteed sorted. */
end;
end;
end;
end comb_sort;

## PowerShell

Massaging gap to always hit 11. Based on PowerShell from Cocktail Sort

function CombSort ($a) {$l = $a.Length$gap = 11
while( $gap -lt$l )
{
$gap = [Math]::Floor($gap*1.3 )
}
if( $l -gt 1 ) {$hasChanged = $true :outer while ($hasChanged -or ( $gap -gt 1 ) ) {$count = 0
$hasChanged =$false
if( $gap -gt 1 ) {$gap = [Math]::Floor( $gap/1.3 ) } else {$l--
}
for ($i = 0;$i -lt ( $l -$gap ); $i++) { if ($a[$i] -gt$a[$i+$gap]) {
$a[$i], $a[$i+$gap] =$a[$i+$gap], $a[$i]
$hasChanged =$true
$count++ } } } }$a
}

$l = 100; CombSort ( 1..$l | ForEach-Object { $Rand = New-Object Random }{$Rand.Next( -( $l - 1 ),$l - 1 ) } )

## PureBasic

Implementation of CombSort11.

;sorts an array of integers
Procedure combSort11(Array a(1))
Protected i, gap, swaps = 1
Protected nElements = ArraySize(a())

gap = nElements
While (gap > 1) Or (swapped = 1)
gap * 10 / 13
If gap = 9 Or gap = 10: gap = 11: EndIf
If gap < 1: gap = 1: EndIf

i = 0
swaps = 0
While (i + gap) <= nElements
If a(i) > a(i + gap)
Swap a(i), a(i + gap)
swaps = 1
EndIf
i + 1
Wend
Wend
EndProcedure

Implementation of CombSort.

;sorts an array of integers
Procedure combSort(Array a(1))
Protected i, gap, swaps = 1
Protected nElements = ArraySize(a())

gap = nElements
While (gap > 1) Or (swaps = 1)
gap = Int(gap / 1.25)

i = 0
swaps = 0
While (i + gap) <= nElements
If a(i) > a(i + gap)
Swap a(i), a(i + gap)
swaps = 1
EndIf
i + 1
Wend
Wend
EndProcedure

## Python

>>> def combsort(input):
gap = len(input)
swaps = True
while gap > 1 or swaps:
gap = max(1, int(gap / 1.25)) # minimum gap is 1
swaps = False
for i in range(len(input) - gap):
j = i+gap
if input[i] > input[j]:
input[i], input[j] = input[j], input[i]
swaps = True

>>> y = [88, 18, 31, 44, 4, 0, 8, 81, 14, 78, 20, 76, 84, 33, 73, 75, 82, 5, 62, 70]
>>> combsort(y)
>>> assert y == sorted(y)
>>> y
[0, 4, 5, 8, 14, 18, 20, 31, 33, 44, 62, 70, 73, 75, 76, 78, 81, 82, 84, 88]
>>>

## R

comb.sort<-function(a){
gap<-length(a)
swaps<-1
while(gap>1 & swaps==1){
gap=floor(gap/1.3)
if(gap<1){
gap=1
}
swaps=0
i=1
while(i+gap<=length(a)){
if(a[i]>a[i+gap]){
a[c(i,i+gap)] <- a[c(i+gap,i)]
swaps=1
}
i<-i+1
}
}
return(a)
}

## Racket

#lang racket
(require (only-in srfi/43 vector-swap!))

(define (comb-sort xs)
(define (ref i) (vector-ref xs i))
(define (swap i j) (vector-swap! xs i j))
(define (new gap) (max 1 (exact-floor (/ gap 1.25))))
(define size (vector-length xs))
(let loop ([gap size] [swaps 0])
(unless (and (= gap 1) (= swaps 0))
(loop (new gap)
(for/fold ([swaps 0]) ([i (in-range 0 (- size gap))])
(cond
[(> (ref i) (ref (+ i gap)))
(swap i (+ i gap))
(+ swaps 1)]
[swaps])))))
xs)

## REXX

/*REXX program  sorts  and displays  a  stemmed array  using the  comb sort  algorithm. */
call gen; w=length(#) /*generate the @ array elements. */
call show 'before sort' /*display the before array elements. */
say copies('▒', 60) /*display a separator line (a fence). */
call combSort # /*invoke the comb sort (with # entries)*/
call show ' after sort' /*display the after array elements. */
exit /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
combSort: procedure expose @.; parse arg N /*N: is the number of @ elements. */
g=N - 1 /*G: is the gap between the sort COMBs*/
do until g<=1 & done; done=1 /*assume sort is done (so far). */
g=g * 0.8  % 1 /*equivalent to: g=trunc( g / 1.25) */
if g==0 then g=1 /*handle case of the gap is too small. */
do j=1 until $>= N;$=j + g /*$: temp index variable. */ if @.j > @.$ then do; [email protected].j; @.[email protected].$; @.$=_; done=0; end
end /*j*/
end /*until*/ /* [↑] swap two elements in the array.*/
return
/*──────────────────────────────────────────────────────────────────────────────────────*/
gen: @. =  ; @.12 = "dodecagon 12"
@.1 = '----polygon--- sides'  ; @.13 = "tridecagon 13"
@.2 = '============== ======='  ; @.14 = "tetradecagon 14"
@.3 = 'triangle 3'  ; @.15 = "pentadecagon 15"
@.5 = 'pentagon 5'  ; @.17 = "heptadecagon 17"
@.6 = 'hexagon 6'  ; @.18 = "octadecagon 18"
@.7 = 'heptagon 7'  ; @.19 = "enneadecagon 19"
@.8 = 'octagon 8'  ; @.20 = "icosagon 20"
@.9 = 'nonagon 9'  ; @.21 = "hectogon 100"
@.10 = 'decagon 10'  ; @.22 = "chiliagon 1000"
@.11 = 'hendecagon 11'  ; @.23 = "myriagon 10000"
do #=1 while @.#\==''; end; #=#-1 /*find how many elements in @*/
return /* [↑] adjust # because of the DO loop*/
/*──────────────────────────────────────────────────────────────────────────────────────*/
show: do k=1 for #; say right('element',15) right(k,w) arg(1)":" @.k; end; return

Data trivia:   A   hendecagon   (also known as an   undecagon   or   unidecagon)   is from the Greek word   hendeka   [eleven]   and   gon─   [corner].

output:
element  1 before sort: ----polygon---  sides
element  2 before sort: ============== =======
element  3 before sort: triangle           3
element  4 before sort: quadrilateral      4
element  5 before sort: pentagon           5
element  6 before sort: hexagon            6
element  7 before sort: heptagon           7
element  8 before sort: octagon            8
element  9 before sort: nonagon            9
element 10 before sort: decagon           10
element 11 before sort: hendecagon        11
element 12 before sort: dodecagon         12
element 13 before sort: tridecagon        13
element 14 before sort: tetradecagon      14
element 15 before sort: pentadecagon      15
element 16 before sort: hexadecagon       16
element 17 before sort: heptadecagon      17
element 18 before sort: octadecagon       18
element 19 before sort: enneadecagon      19
element 20 before sort: icosagon          20
element 21 before sort: hectogon         100
element 22 before sort: chiliagon       1000
element 23 before sort: myriagon       10000
▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒
element  1  after sort: ----polygon---  sides
element  2  after sort: ============== =======
element  3  after sort: chiliagon       1000
element  4  after sort: decagon           10
element  5  after sort: dodecagon         12
element  6  after sort: enneadecagon      19
element  7  after sort: hectogon         100
element  8  after sort: hendecagon        11
element  9  after sort: heptadecagon      17
element 10  after sort: heptagon           7
element 11  after sort: hexadecagon       16
element 12  after sort: hexagon            6
element 13  after sort: icosagon          20
element 14  after sort: myriagon       10000
element 15  after sort: nonagon            9
element 16  after sort: octadecagon       18
element 17  after sort: octagon            8
element 18  after sort: pentadecagon      15
element 19  after sort: pentagon           5
element 20  after sort: quadrilateral      4
element 21  after sort: tetradecagon      14
element 22  after sort: triangle           3
element 23  after sort: tridecagon        13

## Ring

aList = [3,5,1,2,7,4,8,3,6,4,1]
see combsort(aList)

func combsort t
gapd = 1.2473
gap = len(t)
swaps = 0
while gap + swaps > 1
k = 0
swaps = 0
if gap > 1 gap = floor(gap / gapd) ok
for k = 1 to len(t) - gap
if t[k] > t[k + gap]
temp = t[k]
t[k] = t[k + gap]
t[k + gap] = temp
swaps = swaps + 1 ok
next
end
return t

## Ruby

class Array
def combsort!
gap = size
swaps = true
while gap > 1 or swaps
gap = [1, (gap / 1.25).to_i].max
swaps = false
0.upto(size - gap - 1) do |i|
if self[i] > self[i+gap]
self[i], self[i+gap] = self[i+gap], self[i]
swaps = true
end
end
end
self
end
end

p [23, 76, 99, 58, 97, 57, 35, 89, 51, 38, 95, 92, 24, 46, 31, 24, 14, 12, 57, 78].combsort!

results in

[12, 14, 23, 24, 24, 31, 35, 38, 46, 51, 57, 57, 58, 76, 78, 89, 92, 95, 97, 99]

## Scala

### Imperative version (Ugly, side effects)

object CombSort extends App {
val ia = Array(28, 44, 46, 24, 19, 2, 17, 11, 25, 4)
val ca = Array('X', 'B', 'E', 'A', 'Z', 'M', 'S', 'L', 'Y', 'C')

def sorted[E](input: Array[E])(implicit ord: Ordering[E]): Array[E] = {
import ord._
var gap = input.length
var swapped = true
while (gap > 1 || swapped) {
if (gap > 1) gap = (gap / 1.3).toInt
swapped = false
for (i <- 0 until input.length - gap)
if (input(i) >= input(i + gap)) {
val t = input(i)
input(i) = input(i + gap)
input(i + gap) = t
swapped = true
}
}
input
}

println(s"Unsorted : ${ia.mkString("[", ", ", "]")}") println(s"Sorted :${sorted(ia).mkString("[", ", ", "]")}\n")

println(s"Unsorted : ${ca.mkString("[", ", ", "]")}") println(s"Sorted :${sorted(ca).mkString("[", ", ", "]")}")

}
Output:
See it in running in your browser by ScalaFiddle (JavaScript) or by Scastie (JVM).

class SORT{T < $IS_LT{T}} is private swap(inout a, inout b:T) is temp ::= a; a := b; b := temp; end; -- --------------------------------------------------------------------------------- comb_sort(inout a:ARRAY{T}) is gap ::= a.size; swapped ::= true; loop until!(gap <= 1 and ~swapped); if gap > 1 then gap := (gap.flt / 1.25).int; end; i ::= 0; swapped := false; loop until! ( (i + gap) >= a.size ); if (a[i] > a[i+gap]) then swap(inout a[i], inout a[i+gap]); swapped := true; end; i := i + 1; end; end; end; end; class MAIN is main is a:ARRAY{INT} := |88, 18, 31, 44, 4, 0, 8, 81, 14, 78, 20, 76, 84, 33, 73, 75, 82, 5, 62, 70|; b ::= a.copy; SORT{INT}::comb_sort(inout b); #OUT + b + "\n"; end; end; ## Sidef func comb_sort(arr) { var gap = arr.len; var swaps = true; while (gap > 1 || swaps) { gap.div!(1.25).int! if (gap > 1); swaps = false; for i in ^(arr.len - gap) { if (arr[i] > arr[i+gap]) { arr[i, i+gap] = arr[i+gap, i]; swaps = true; } } } return arr; } ## Swift Translation of: C func combSort(inout list:[Int]) { var swapped = true var gap = list.count while gap > 1 || swapped { gap = gap * 10 / 13 if gap == 9 || gap == 10 { gap = 11 } else if gap < 1 { gap = 1 } swapped = false for var i = 0, j = gap; j < list.count; i++, j++ { if list[i] > list[j] { (list[i], list[j]) = (list[j], list[i]) swapped = true } } } } ## Tcl proc combsort {input} { set gap [llength$input]
while 1 {
set gap [expr {int(floor($gap / 1.3))}] set swaps 0 for {set i 0} {$i+$gap < [llength$input]} {incr i} {
set j [expr {$i+$gap}]
if {[lindex $input$i] > [lindex $input$j]} {
set tmp [lindex $input$i]
lset input $i [lindex$input $j] lset input$j $tmp incr swaps } } if {$gap <= 1 && !$swaps} break } return$input
}

set data {23 76 99 58 97 57 35 89 51 38 95 92 24 46 31 24 14 12 57 78}
puts [combsort \$data]

Produces this output:

12 14 23 24 24 31 35 38 46 51 57 57 58 76 78 89 92 95 97 99

## TI-83 BASIC

Requires prgmSORTINS. Gap division of 1.3. Switches to Insertion sort when gap is less than 5.

:L1→L2
:dim(L2)→A
:While A>5 and B=0
:int(A/1.3)→A
:1→C
:0→B
:While (C+A)≥dim(L2)
:If L2(C)>L2(C+A)
:Then
:L2(C)→D
:L2(C+A)→L2(C)
:D→L2(C+A)
:1→B
:End
:C+1→C
:End
:DelVar A
:DelVar B
:DelVar C
:DelVar D
:L1→L3
:L2→L1
:prgmSORTINS
:L3→L1
:DelVar L3
:Return

## uBasic/4tH

PRINT "Comb sort:"
n = FUNC (_InitArray)
PROC _ShowArray (n)
PROC _Combsort (n)
PROC _ShowArray (n)
PRINT

END

_Combsort PARAM (1) ' Combsort subroutine
LOCAL(4)
[email protected] = [email protected]
[email protected] = 1

DO WHILE ([email protected] > 1) + [email protected]

[email protected] = ([email protected] * 10) / 13

IF ([email protected] = 9) + ([email protected] = 10) THEN [email protected] = 11
IF [email protected] < 1 THEN [email protected] = 1

[email protected] = 0
[email protected] = 0
[email protected] = [email protected]

DO WHILE [email protected] < [email protected]
IF @([email protected]) > @([email protected]) THEN PROC _Swap ([email protected], [email protected]) : [email protected] = 1
[email protected] = [email protected] + 1
[email protected] = [email protected] + 1
LOOP
LOOP
RETURN

_Swap PARAM(2) ' Swap two array elements
PUSH @([email protected])
@([email protected]) = @([email protected])
@([email protected]) = POP()
RETURN

_InitArray ' Init example array
PUSH 4, 65, 2, -31, 0, 99, 2, 83, 782, 1

FOR i = 0 TO 9
@(i) = POP()
NEXT

RETURN (i)

_ShowArray PARAM (1) ' Show array subroutine
FOR i = 0 TO [email protected]
PRINT @(i),
NEXT

PRINT
RETURN

## VBA

{[trans|Phix}}
Function comb_sort(ByVal s As Variant) As Variant
Dim gap As Integer: gap = UBound(s)
Dim swapped As Integer
Do While True
gap = WorksheetFunction.Max(WorksheetFunction.Floor_Precise(gap / 1.3), 1)
swapped = False
For i = 0 To UBound(s) - gap
si = Val(s(i))
If si > Val(s(i + gap)) Then
s(i) = s(i + gap)
s(i + gap) = CStr(si)
swapped = True
End If
Next i
If gap = 1 And Not swapped Then Exit Do
Loop
comb_sort = s
End Function

Public Sub main()
Dim s(9) As Variant
For i = 0 To 9
s(i) = CStr(Int(1000 * Rnd))
Next i
Debug.Print Join(s, ", ")
Debug.Print Join(comb_sort(s), ", ")
End Sub
Output:
45, 414, 862, 790, 373, 961, 871, 56, 949, 364
45, 56, 364, 373, 414, 790, 862, 871, 949, 961

## zkl

Translation of: D
fcn combSort(list){
len,gap,swaps:=list.len(),len,True;
while(gap>1 or swaps){
gap,swaps=(1).max(gap.toFloat()/1.2473), False;
foreach i in (len - gap){
if(list[i]>list[i + gap]){
list.swap(i,i + gap);
swaps=True;
}
}
}
list
}
combSort(List(28, 44, 46, 24, 19, 2, 17, 11, 25, 4)).println();
combSort("This is a test".toData()).text.println();
Output:
L(2,4,11,17,19,24,25,28,44,46)
Taehiissstt