Sorting algorithms/Bubble sort: Difference between revisions

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In this task, the goal is to sort an array of elements using the bubble sort algorithm. The elements must have a total order and the index of the array can be of any discrete type. For languages where this is not possible, sort an array of integers.

The bubble sort is generally considered to be the simplest sorting algorithm. Because of its simplicity and ease of visualization, it is often taught in introductory computer science courses. Because of its abysmal O(n²) performance, it is not used often for large (or even medium-sized) datasets.

The bubble sort works by passing sequentially over a list, comparing each value to the one immediately after it. If the first value is greater than the second, their positions are switched. Over a number of passes, at most equal to the number of elements in the list, all of the values drift into their correct positions (large values "bubble" rapidly toward the end, pushing others down around them). Because each pass finds the maximum item and puts it at the end, the portion of the list to be sorted can be reduced at each pass. A boolean variable is used to track whether any changes have been made in the current pass; when a pass completes without changing anything, the algorithm exits.

This can be expressed in pseudocode as follows (assuming 1-based indexing):

repeat
    hasChanged := false
    decrement itemCount
    repeat with index from 1 to itemCount
        if (item at index) > (item at (index + 1))
            swap (item at index) with (item at (index + 1))
            hasChanged := true
until hasChanged = false

References

The article on Wikipedia.
Dance interpretation.

ActionScript

<lang actionscript>public function bubbleSort(toSort:Array):Array { var changed:Boolean = false;

while (!changed) { changed = true;

for (var i:int = 0; i < toSort.length - 1; i++) { if (toSort[i] > toSort[i + 1]) { var tmp:int = toSort[i]; toSort[i] = toSort[i + 1]; toSort[i + 1] = tmp;

changed = false; } } }

return toSort; }</lang>

Ada

Works with: GCC version 4.1.2

<lang ada>generic

type Element is private;
with function "=" (E1, E2 : Element) return Boolean is <>;
with function "<" (E1, E2 : Element) return Boolean is <>;
type Index is (<>);
type Arr is array (Index range <>) of Element;

procedure Bubble_Sort (A : in out Arr);

procedure Bubble_Sort (A : in out Arr) is

Finished : Boolean;
Temp     : Element;

begin

loop
 Finished := True;
 for J in A'First .. Index'Pred (A'Last) loop
  if A (Index'Succ (J)) < A (J) then
   Finished := False;
   Temp := A (Index'Succ (J));
   A (Index'Succ (J)) := A (J);
   A (J) := Temp;
  end if;
 end loop;
 exit when Finished;
end loop;

end Bubble_Sort;

-- Example of usage: with Ada.Text_IO; use Ada.Text_IO; with Bubble_Sort; procedure Main is

type Arr is array (Positive range <>) of Integer;
procedure Sort is new
 Bubble_Sort
  (Element => Integer,
   Index   => Positive,
   Arr     => Arr);
A : Arr := (1, 3, 256, 0, 3, 4, -1);

begin

Sort (A);
for J in A'Range loop
 Put (Integer'Image (A (J)));
end loop;
New_Line;

end Main;</lang>

ALGOL 68

<lang algol68>MODE DATA = INT; PROC swap = (REF[]DATA slice)VOID: (

 DATA tmp = slice[1];
 slice[1] := slice[2];
 slice[2] := tmp

);

PROC sort = (REF[]DATA array)VOID: (

 BOOL sorted;
 INT shrinkage := 0;
 FOR size FROM UPB array - 1 BY -1 WHILE
   sorted := TRUE;
   shrinkage +:= 1;
   FOR i FROM LWB array TO size DO
     IF array[i+1] < array[i] THEN
       swap(array[i:i+1]);
       sorted := FALSE
     FI
   OD;
   NOT sorted
 DO SKIP OD

);

main:(

 [10]INT random := (1,6,3,5,2,9,8,4,7,0);

 printf(($"Before: "10(g(3))l$,random));
 sort(random);
 printf(($"After: "10(g(3))l$,random))

)</lang> Output:

Before:  +1 +6 +3 +5 +2 +9 +8 +4 +7 +0
After:  +0 +1 +2 +3 +4 +5 +6 +7 +8 +9

AutoHotkey

<lang AutoHotkey>var = ( dog cat pile abc ) MsgBox % bubblesort(var)

bubblesort(var) ; each line of var is an element of the array {

 StringSplit, array, var, `n
 hasChanged = 1
 size := array0
 While hasChanged
 {
   hasChanged = 0
   Loop, % (size - 1)
   {
     i := array%A_Index%
     aj := A_Index + 1
     j := array%aj%
     If (j < i)
     {
       temp := array%A_Index%
       array%A_Index% := array%aj%
       array%aj% := temp
       hasChanged = 1
     } 
   }
 }
 Loop, % size
   sorted .= array%A_Index% . "`n"
 Return sorted

}</lang>

AWK

Sort the standard input and print it to standard output. <lang awk>{ # read every line into an array

 line[NR] = $0

} END { # sort it with bubble sort

 do {
   haschanged = 0
   for(i=1; i < NR; i++) {
     if ( line[i] > line[i+1] ) {

t = line[i] line[i] = line[i+1] line[i+1] = t haschanged = 1

     }
   }
 } while ( haschanged == 1 )
 # print it
 for(i=1; i <= NR; i++) {
   print line[i]
 }

}</lang>

BASIC

Works with: QuickBasic version 4.5

Translation of: Java

Assume numbers are in a DIM of size "size" called "nums". <lang qbasic>DO

changed = 0
for I = 1 to size -1
   IF nums(I) > nums(I + 1) THEN
       tmp = nums(I)
       nums(I) = nums(I + 1)
       nums(I + 1) = tmp
       changed = 1
   END IF

LOOP WHILE(NOT changed)</lang>

BBC BASIC

The Bubble sort is very inefficient for 99% of cases. This subroutine uses a couple of 'tricks' to try and mitigate the inefficiency to a limited extent. <lang bbcbasic>DEF PROC_BubbleSort(Size%)

I%=Size%+1 REPEAT

 I%-=1
 LastChange%=2
 FOR J% = 2 TO I%
   IF data%(J%-1) > data%(J%) THEN
      SWAP data%(J%-1),data%(J%)
      LastChange%=J%
   ENDIF
 NEXT J%
 I%=LastChange%

UNTIL I% = 2

ENDPROC</lang>

C

<lang c>void bubble_sort(int *a, int n) { int j, t = 1; while (n-- && t) for (j = t = 0; j < n; j++) { if (a[j] <= a[j + 1]) continue; t = a[j], a[j] = a[j + 1], a[j + 1] = t; t=1; } }

int main(void) { int a[] = {4, 65, 2, -31, 0, 99, 2, 83, 782, 1}; bubble_sort(a, sizeof(a) / sizeof(a[0]));

return 0; }</lang>

C++

Works with: g++ version 4.0.2

<lang cpp>#include <iostream>

include <algorithm>

template< typename ARRAY_TYPE, typename INDEX_TYPE > void bubble_sort(ARRAY_TYPE array[], INDEX_TYPE size) {

   bool done = false;

   while ( ! done)
   {
       done = true;
       for (INDEX_TYPE i = 0 ; i < size-1 ; i++)
       {
           if (array[i] > array[i+1])
           {
               done = false;
               std::swap(array[i], array[i+1]);
           }
       }
       size--;
   }

}

template< typename TYPE > void print(TYPE val) {

   std::cout << val << " ";

}

int main() {

   int array[] = { 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 };
   bubble_sort(array, 10);
   std::for_each (&array[0], &array[10], print<int>);
   std::cout << std::endl;

   //But in real life...
   int data[] = { 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 };
   std::sort(data, data+10);
   std::for_each (data, data+10, print<int>);
   std::cout << std::endl;

}</lang>

C#

Works with: C# version 3.0+

<lang csharp>using System; using System.Collections.Generic;

namespace RosettaCode.BubbleSort {

   public static class BubbleSortMethods
   {
       //The "this" keyword before the method parameter identifies this as a C# extension
       //method, which can be called using instance method syntax on any generic list,
       //without having to modify the generic List<T> code provided by the .NET framework.
       public static void BubbleSort<T>(this List<T> list) where T : IComparable
       {
           bool madeChanges;
           int itemCount = list.Count;
           do
           {
               madeChanges = false;
               itemCount--;
               for (int i = 0; i < itemCount; i++)
               {
                   if (list[i].CompareTo(list[i + 1]) > 0)
                   {
                       T temp = list[i + 1];
                       list[i + 1] = list[i];
                       list[i] = temp;
                       madeChanges = true;
                   }
               }
           } while (madeChanges);
       }
   }

   //A short test program to demonstrate the BubbleSort. The compiler will change the
   //call to testList.BubbleSort() into one to BubbleSortMethods.BubbleSort<T>(testList).
   class Program
   {
       static void Main()
       {
           List<int> testList = new List<int> { 3, 7, 3, 2, 1, -4, 10, 12, 4 };
           testList.BubbleSort();
           foreach (var t in testList) Console.Write(t + " ");
       }
   }

}</lang>

Clean

Bubble sorting an array in-situ (using destructive updates), using Clean's uniqueness typing. We specified the type of sweep using strictness annotations to improve performance. <lang clean>import StdEnv

bsort :: *(a e) -> *(a e) | Array a e & < e bsort array

   # (done, array) = sweep 1 True array
   = if done array (bsort array)

where

   sweep :: !Int !Bool !*(a e) -> (!Bool, !*(a e)) | Array a e & < e
   sweep i done array
       | i >= size array = (done, array)
       # (e1, array) = array![i - 1]
         (e2, array) = array![i]
       | e1 > e2 = sweep (i + 1) False {array & [i - 1] = e2, [i] = e1}
       = sweep (i + 1) done array</lang>

Using it to sort an array of a hundred numbers: <lang clean>Start :: {Int} Start = bsort {x \\ x <- [100,99..1]}</lang>

Clojure

Bubble sorts a Java ArrayList in place. Uses 'doseq' iteration construct with a short-circuit when a pass didn't produce any change, and within the pass, an atomic 'changed' variable that gets reset whenever a change occurs.

<lang clojure>(ns bubblesort

 (:import java.util.ArrayList))

(defn bubble-sort

 "Sort in-place.
 arr must implement the Java List interface and should support
 random access, e.g. an ArrayList."
 ([arr] (bubble-sort compare arr))
 ([cmp arr]
    (letfn [(swap! [i j]
                   (let [t (.get arr i)]
                     (doto arr
                       (.set i (.get arr j))
                       (.set j t))))
            (sorter [stop-i]
                    (let [changed (atom false)]
                      (doseq [i (range stop-i)]
                        (if (pos? (cmp (.get arr i) (.get arr (inc i))))
                          (do
                            (swap! i (inc i))
                            (reset! changed true))))
                      @changed))]
      (doseq [stop-i (range (dec (.size arr)) -1 -1)
              :while (sorter stop-i)])
      arr)))

(println (bubble-sort (ArrayList. [10 9 8 7 6 5 4 3 2 1])))</lang>

Purely functional version working on Clojure sequences: <lang clojure>(defn- bubble-step

 "was-changed: whether any elements prior to the current first element
 were swapped;
 returns a two-element vector [partially-sorted-sequence is-sorted]"
[less? xs was-changed]
 (if (< (count xs) 2)
   [xs (not was-changed)]
   (let [[x1 x2 & xr] xs

first-is-smaller (less? x1 x2) is-changed (or was-changed (not first-is-smaller)) [smaller larger] (if first-is-smaller [x1 x2] [x2 x1]) [result is-sorted] (bubble-step less? (cons larger xr) is-changed)]

     [(cons smaller result) is-sorted])))

(defn bubble-sort

 "Takes an optional less-than predicate and a sequence.
 Returns the sorted sequence.
 Very inefficient (O(n²))"
 ([xs] (bubble-sort <= xs))
 ([less? xs] 
    (let [[result is-sorted] (bubble-step less? xs false)]
      (if is-sorted

result (recur less? result)))))

(println (bubble-sort [10 9 8 7 6 5 4 3 2 1]))</lang>

CMake

Only for lists of integers.

<lang cmake># bubble_sort(var [value1 value2...]) sorts a list of integers. function(bubble_sort var)

 math(EXPR last "${ARGC} - 1")  # Prepare to sort ARGV[1]..ARGV[last].
 set(again YES)
 while(again)
   set(again NO)
   math(EXPR last "${last} - 1")               # Decrement last index.
   foreach(index RANGE 1 ${last})              # Loop for each index.
     math(EXPR index_plus_1 "${index} + 1")
     set(a "${ARGV${index}}")                  # a = ARGV[index]
     set(b "${ARGV${index_plus_1}}")           # b = ARGV[index + 1]
     if(a GREATER "${b}")                      # If a > b...
       set(ARGV${index} "${b}")                # ...then swap a, b
       set(ARGV${index_plus_1} "${a}")         #    inside ARGV.
       set(again YES)
     endif()
   endforeach(index)
 endwhile()

 set(answer)
 math(EXPR last "${ARGC} - 1")
 foreach(index RANGE 1 "${last}")
   list(APPEND answer "${ARGV${index}}")
 endforeach(index)
 set("${var}" "${answer}" PARENT_SCOPE)

endfunction(bubble_sort)</lang>

<lang cmake>bubble_sort(result 33 11 44 22 66 55) message(STATUS "${result}")</lang>

-- 11;22;33;44;55;66

COBOL

This is a complete program that reads in a file of integers and sorts them. <lang cobol> IDENTIFICATION DIVISION.

      PROGRAM-ID.                      BUBBLESORT.
      AUTHOR.                          DAVE STRATFORD.
      DATE-WRITTEN.                    MARCH 2010.
      INSTALLATION.                    HEXAGON SYSTEMS LIMITED.

      ENVIRONMENT DIVISION.
      CONFIGURATION SECTION.
      SOURCE-COMPUTER.                 ICL VME.
      OBJECT-COMPUTER.                 ICL VME.

      INPUT-OUTPUT SECTION.
      FILE-CONTROL.
          SELECT FA-INPUT-FILE  ASSIGN FL01.
          SELECT FB-OUTPUT-FILE ASSIGN FL02.

      DATA DIVISION.
      FILE SECTION.

      FD  FA-INPUT-FILE.
      01  FA-INPUT-REC.
        03  FA-DATA                    PIC S9(6).

      FD  FB-OUTPUT-FILE.
      01  FB-OUTPUT-REC                PIC S9(6).

      WORKING-STORAGE SECTION.
      01  WA-IDENTITY.
        03  WA-PROGNAME                PIC X(10) VALUE "BUBBLESORT".
        03  WA-VERSION                 PIC X(6) VALUE "000001".

      01  WB-TABLE.
        03  WB-ENTRY                   PIC 9(8) COMP SYNC OCCURS 100000
                                                 INDEXED BY WB-IX-1.

      01  WC-VARS.
        03  WC-SIZE                    PIC S9(8) COMP SYNC.
        03  WC-TEMP                    PIC S9(8) COMP SYNC.
        03  WC-END                     PIC S9(8) COMP SYNC.
        03  WC-LAST-CHANGE             PIC S9(8) COMP SYNC.

      01  WF-CONDITION-FLAGS.
        03  WF-EOF-FLAG                PIC X.
          88  END-OF-FILE              VALUE "Y".
        03  WF-EMPTY-FILE-FLAG         PIC X.
          88  EMPTY-FILE               VALUE "Y".

      PROCEDURE DIVISION.
      A-MAIN SECTION.
      A-000.
          PERFORM B-INITIALISE.
          IF NOT EMPTY-FILE
             PERFORM C-SORT.
          PERFORM D-FINISH.

      A-999.
          STOP RUN.

      B-INITIALISE SECTION.
      B-000.
          DISPLAY "*** " WA-PROGNAME " VERSION "
                         WA-VERSION " STARTING ***".

          MOVE ALL "N" TO WF-CONDITION-FLAGS.
          OPEN INPUT FA-INPUT-FILE.
          SET WB-IX-1 TO 0.

          READ FA-INPUT-FILE AT END MOVE "Y" TO WF-EOF-FLAG
                                                WF-EMPTY-FILE-FLAG.

          PERFORM BA-READ-INPUT UNTIL END-OF-FILE.

          CLOSE FA-INPUT-FILE.

          SET WC-SIZE TO WB-IX-1.

      B-999.
          EXIT.

      BA-READ-INPUT SECTION.
      BA-000.
          SET WB-IX-1 UP BY 1.
          MOVE FA-DATA TO WB-ENTRY(WB-IX-1).

          READ FA-INPUT-FILE AT END MOVE "Y" TO WF-EOF-FLAG.

      BA-999.
          EXIT.

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

          MOVE WC-SIZE TO WC-END.
          PERFORM E-BUBBLE UNTIL WC-END = 1.

          DISPLAY "SORT FINISHED".

      C-999.
          EXIT.

      D-FINISH SECTION.
      D-000.
          OPEN OUTPUT FB-OUTPUT-FILE.
          SET WB-IX-1 TO 1.

          PERFORM DA-WRITE-OUTPUT UNTIL WB-IX-1 > WC-SIZE.

          CLOSE FB-OUTPUT-FILE.

          DISPLAY "*** " WA-PROGNAME " FINISHED ***".

      D-999.
          EXIT.

      DA-WRITE-OUTPUT SECTION.
      DA-000.
          WRITE FB-OUTPUT-REC FROM WB-ENTRY(WB-IX-1).
          SET WB-IX-1 UP BY 1.

      DA-999.
          EXIT.

      E-BUBBLE SECTION.
      E-000.
          MOVE 1 TO WC-LAST-CHANGE.

          PERFORM F-PASS VARYING WB-IX-1 FROM 1 BY 1
                         UNTIL WB-IX-1 = WC-END.

          MOVE WC-LAST-CHANGE TO WC-END.

      E-999.
          EXIT.

      F-PASS SECTION.
      F-000.
          IF WB-ENTRY(WB-IX-1) > WB-ENTRY(WB-IX-1 + 1)
             SET  WC-LAST-CHANGE        TO WB-IX-1
             MOVE WB-ENTRY(WB-IX-1)     TO WC-TEMP
             MOVE WB-ENTRY(WB-IX-1 + 1) TO WB-ENTRY(WB-IX-1)
             MOVE WC-TEMP               TO WB-ENTRY(WB-IX-1 + 1).

      F-999.
          EXIT.</lang>

Common Lisp

Bubble sort an sequence in-place, using the < operator for comparison if no comaprison function is provided <lang lisp>(defun bubble-sort (sequence &optional (compare #'<))

 "sort a sequence (array or list) with an optional comparison function (cl:< is the default)"
 (loop with sorted = nil until sorted do
       (setf sorted t)
       (loop for a below (1- (length sequence)) do
             (unless (funcall compare (elt sequence a)
                                      (elt sequence (1+ a)))
               (rotatef (elt sequence a)
                        (elt sequence (1+ a)))
               (setf sorted nil)))))</lang>

<lang lisp>(bubble-sort (list 5 4 3 2 1))</lang>

elt has linear access time for lists, making the prior implementation of bubble-sort very expensive (although very clear, and straightforward to code. Here is an implementation that works efficiently for both vectors and lists. For lists it also has the nice property that the input list and the sorted list begin with the same cons cell.

<lang lisp>(defun bubble-sort-vector (vector predicate &aux (len (1- (length vector))))

 (do ((swapped t)) ((not swapped) vector)
   (setf swapped nil)
   (do ((i (min 0 len) (1+ i))) ((eql i len))
     (when (funcall predicate (aref vector (1+ i)) (aref vector i))
       (rotatef (aref vector i) (aref vector (1+ i)))
       (setf swapped t)))))

(defun bubble-sort-list (list predicate)

 (do ((swapped t)) ((not swapped) list)
   (setf swapped nil)
   (do ((list list (rest list))) ((endp (rest list)))
     (when (funcall predicate (second list) (first list))
       (rotatef (first list) (second list))
       (setf swapped t)))))

(defun bubble-sort (sequence predicate)

 (etypecase sequence
   (list (bubble-sort-list sequence predicate))
   (vector (bubble-sort-vector sequence predicate))))</lang>

D

<lang d>import std.stdio, std.algorithm;

void bubbleSort(T)(T[] data) pure nothrow {

   int itemCount = data.length;
   bool hasChanged = false;

   do {
       hasChanged = false;
       itemCount--;
       foreach (i; 0 .. itemCount)
           if (data[i] > data[i + 1]) {
               swap(data[i], data[i + 1]);
               hasChanged = true;
           }
   } while (hasChanged);

}

void main() {

   auto array = [28, 44, 46, 24, 19, 2, 17, 11, 25, 4];
   array.bubbleSort();
   writeln(array);

}</lang> Output:

[2, 4, 11, 17, 19, 24, 25, 28, 44, 46]

Delphi

Dynamic array is a 0-based array of variable length

Static array is an arbitrary-based array of fixed length <lang Delphi>program TestBubbleSort;

{$APPTYPE CONSOLE}

{.$DEFINE DYNARRAY} // remove '.' to compile with dynamic array

type

 TItem = Integer;   // declare ordinal type for array item

{$IFDEF DYNARRAY}

 TArray = array of TItem;          // dynamic array

{$ELSE}

 TArray = array[0..15] of TItem;   // static array

{$ENDIF}

procedure BubbleSort(var A: TArray); var

 Item: TItem;
 K, L, J: Integer;

begin

 L:= Low(A) + 1;
 repeat
   K:= High(A);
   for J:= High(A) downto L do begin
     if A[J - 1] > A[J] then begin
       Item:= A[J - 1];
       A[J - 1]:= A[J];
       A[J]:= Item;
       K:= J;
     end;
   end;
   L:= K + 1;
 until L > High(A);

end;

var

 A: TArray;
 I: Integer;

begin {$IFDEF DYNARRAY}

 SetLength(A, 16);

{$ENDIF}

 for I:= Low(A) to High(A) do
   A[I]:= Random(100);
 for I:= Low(A) to High(A) do
   Write(A[I]:3);
 Writeln;
 BubbleSort(A);
 for I:= Low(A) to High(A) do
   Write(A[I]:3);
 Writeln;
 Readln;

end.</lang> Output:

  0  3 86 20 27 67 31 16 37 42  8 47  7 84  5 29
  0  3  5  7  8 16 20 27 29 31 37 42 47 67 84 86

E

<lang e>def bubbleSort(target) {

 __loop(fn {
   var changed := false
   for i in 0..(target.size() - 2) {
     def [a, b] := target(i, i + 2)
     if (a > b) {
       target(i, i + 2) := [b, a]
       changed := true
     }
   }
   changed
 })

}</lang>

(Uses the primitive __loop directly because it happens to map to the termination test for this algorithm well.)

Eiffel

Works with: EiffelStudio version 6.6 (with provisional loop syntax)

This solution is presented in two classes. The first is a simple application that creates a set, an instance of MY_SORTED_SET, and adds elements to the set in unsorted order. It iterates across the set printing the elements, then it sorts the set, and reprints the elements.

<lang eiffel>class

   APPLICATION

create

   make

feature

   make
           -- Create and print sorted set
       do
           create my_set.make
           my_set.put_front (2)
           my_set.put_front (6)
           my_set.put_front (1)
           my_set.put_front (5)
           my_set.put_front (3)
           my_set.put_front (9)
           my_set.put_front (8)
           my_set.put_front (4)
           my_set.put_front (10)
           my_set.put_front (7)
           print ("Before: ")
           across my_set as ic loop print (ic.item.out + " ")  end
           print ("%NAfter : ")
           my_set.sort
           across my_set as ic loop print (ic.item.out + " ")  end
       end

   my_set: MY_SORTED_SET [INTEGER]
           -- Set to be sorted

end</lang>

The second class is MY_SORTED_SET.

<lang eiffel>class

   MY_SORTED_SET [G -> COMPARABLE]

inherit

   TWO_WAY_SORTED_SET [G]
       redefine
           sort
       end

create

   make

feature

   sort
           -- Sort with bubble sort
       local
           l_unchanged: BOOLEAN
           l_item_count: INTEGER
           l_temp: G
       do
           from
               l_item_count := count
           until
               l_unchanged
           loop
               l_unchanged := True
               l_item_count := l_item_count - 1
               across 1 |..| l_item_count as ic loop
                   if Current [ic.item] > Current [ic.item + 1] then
                       l_temp := Current [ic.item]
                       Current [ic.item] := Current [ic.item + 1]
                       Current [ic.item + 1] := l_temp
                       l_unchanged := False
                   end
               end
           end
       end

end</lang>

This class inherits from the Eiffel library class TWO_WAY_SORTED_SET, which implements sets whose elements are comparable. Therefore, the set can be ordered and in fact is kept so under normal circumstances.

MY_SORTED_SET redefines only the routine sort which contains the implementation of the sort algorithm. The implementation in the redefined version of sort in MY_SORTED_SET uses a bubble sort.

Output:

Before: 7 10 4 8 9 3 5 1 6 2
After : 1 2 3 4 5 6 7 8 9 10

TWO_WAY_SORTED_SET is implemented internally as a list. For this example, we use the feature put_front which explicitly adds each new element to the beginning of the list, allowing us to show that the elements are unordered until we sort them. It also causes, in the "Before" output, the elements to be printed in the reverse of the order in which they were added. Under normal circumstances, we would use the feature extend (rather than put_front) to add elements to the list. This would assure that the order was maintained even as elements were added.

Euphoria

<lang euphoria>function bubble_sort(sequence s)

   object tmp
   integer changed
   for j = length(s) to 1 by -1 do
       changed = 0
       for i = 1 to j-1 do
           if compare(s[i], s[i+1]) > 0 then
               tmp = s[i]
               s[i] = s[i+1]
               s[i+1] = tmp
               changed = 1
           end if
       end for
       if not changed then
           exit
       end if
   end for
   return s

end function

include misc.e constant s = {4, 15, "delta", 2, -31, 0, "alfa", 19, "gamma", 2, 13, "beta", 782, 1}

puts(1,"Before: ") pretty_print(1,s,{2}) puts(1,"\nAfter: ") pretty_print(1,bubble_sort(s),{2})</lang>

Output:

Before: {
  4,
  15,
  "delta",
  2,
  -31,
  0,
  "alfa",
  19,
  "gamma",
  2,
  13,
  "beta",
  782,
  1
}
After: {
  -31,
  0,
  1,
  2,
  2,
  4,
  13,
  15,
  19,
  782,
  "alfa",
  "beta",
  "delta",
  "gamma"
}

Factor

<lang factor>USING: fry kernel locals math math.order sequences sequences.private ; IN: rosetta.bubble

<PRIVATE

?exchange ( i seq quot -- ? )

   i i 1 + [ seq nth-unsafe ] bi@ quot call +gt+ = :> doit?
   doit? [ i i 1 + seq exchange ] when
   doit? ; inline

1pass ( seq quot -- ? )

   [ [ length 1 - iota ] keep ] dip
   '[ _ _ ?exchange ] [ or ] map-reduce ; inline

PRIVATE>

sort! ( seq quot -- )

   over empty?
   [ 2drop ] [ '[ _ _ 1pass ] loop ] if ; inline

natural-sort! ( seq -- )

   [ <=> ] sort! ;</lang>

It is possible to pass your own comparison operator to sort!, so you can f.e. sort your sequence backwards with passing [ >=< ] into it.

<lang factor>10 [ 10000 random ] replicate [ "Before: " write . ] [ "Natural: " write [ natural-sort! ] keep . ] [ "Reverse: " write [ [ >=< ] sort! ] keep . ] tri</lang>

Before:  { 3707 5045 4661 1489 3140 7195 8844 6506 6322 3199 }
Natural: { 1489 3140 3199 3707 4661 5045 6322 6506 7195 8844 }
Reverse: { 8844 7195 6506 6322 5045 4661 3707 3199 3140 1489 }

Forth

Sorts the 'cnt' cells stored at 'addr' using the test stored in the deferred word 'bubble-test'. Uses forth local variables for clarity.

<lang forth>defer bubble-test ' > is bubble-test

bubble { addr cnt -- }

 cnt 1 do
   addr cnt i - cells bounds do
     i 2@ bubble-test if i 2@ swap i 2! then
   cell +loop
 loop ;</lang>

This is the same algorithm done without the local variables:

<lang forth>: bubble ( addr cnt -- )

 dup 1 do
   2dup i - cells bounds do
     i 2@ bubble-test if i 2@ swap i 2! then
   cell +loop
 loop ;</lang>

Version with O(n) best case: <lang forth>: bubble ( addr len -- )

 begin
   1- 2dup  true -rot  ( sorted addr len-1 )
   cells bounds ?do
     i 2@ bubble-test if
       i 2@ swap i 2!
       drop false   ( mark unsorted )
     then
   cell +loop  ( sorted )
 until 2drop ;</lang>

Test any version with this:

create test
8 , 1 , 4 , 2 , 10 , 3 , 7 , 9 , 6 , 5 ,
here test - cell / constant tcnt

test tcnt cells dump
' > is bubble-test
test tcnt bubble
test tcnt cells dump
' < is bubble-test
test tcnt bubble
test tcnt cells dump

Fortran

<lang fortran>SUBROUTINE Bubble_Sort(a)

 REAL, INTENT(in out), DIMENSION(:) :: a
 REAL :: temp
 INTEGER :: i, j
 LOGICAL :: swapped = .TRUE.

 DO j = SIZE(a)-1, 1, -1
   swapped = .FALSE.
   DO i = 1, j
     IF (a(i) > a(i+1)) THEN
       temp = a(i)
       a(i) = a(i+1)
       a(i+1) = temp
       swapped = .TRUE.
     END IF
   END DO
   IF (.NOT. swapped) EXIT
 END DO

END SUBROUTINE Bubble_Sort</lang>

Go

Per task pseudocode: <lang go>package main

import "fmt"

func main() {

   list := []int{31, 41, 59, 26, 53, 58, 97, 93, 23, 84}
   fmt.Println("unsorted:", list)

   bubblesort(list)
   fmt.Println("sorted!  ", list)

}

func bubblesort(a []int) {

   for itemCount := len(a) - 1; ; itemCount-- {
       hasChanged := false
       for index := 0; index < itemCount; index++ {
           if a[index] > a[index+1] {
               a[index], a[index+1] = a[index+1], a[index]
               hasChanged = true
           }
       }
       if hasChanged == false {
           break
       }
   }

}</lang>

More generic version that can sort anything that implements sort.Interface: <lang go>package main

import (

 "sort"
 "fmt"

)

func main() {

   list := []int{31, 41, 59, 26, 53, 58, 97, 93, 23, 84}
   fmt.Println("unsorted:", list)

   bubblesort(sort.IntSlice(list))
   fmt.Println("sorted!  ", list)

}

func bubblesort(a sort.Interface) {

   for itemCount := a.Len() - 1; ; itemCount-- {
       hasChanged := false
       for index := 0; index < itemCount; index++ {
           if a.Less(index+1, index) {
               a.Swap(index, index+1)
               hasChanged = true
           }
       }
       if !hasChanged {
           break
       }
   }

}</lang>

Groovy

Solution: <lang groovy>def makeSwap = { a, i, j = i+1 -> print "."; ai,j = aj,i }

def checkSwap = { a, i, j = i+1 -> [(a[i] > a[j])].find { it }.each { makeSwap(a, i, j) } }

def bubbleSort = { list ->

   boolean swapped = true
   while (swapped) { swapped = (1..<list.size()).any { checkSwap(list, it-1) } }
   list

}</lang>

Test Program: <lang groovy>println bubbleSort([23,76,99,58,97,57,35,89,51,38,95,92,24,46,31,24,14,12,57,78,4]) println bubbleSort([88,18,31,44,4,0,8,81,14,78,20,76,84,33,73,75,82,5,62,70,12,7,1])</lang>

Output:

..............................................................................................................................................[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]

Haskell

This version checks for changes in a separate step for simplicity, because Haskell has no variables to track them with. <lang haskell>bsort :: Ord a => [a] -> [a] bsort s = case _bsort s of

              t | t == s    -> t
                | otherwise -> bsort t
 where _bsort (x:x2:xs) | x > x2    = x2:(_bsort (x:xs))
                        | otherwise = x:(_bsort (x2:xs))
       _bsort s = s</lang>

This version uses the polymorphic Maybe type to designate unchanged lists. (The type signature of _bsort is now Ord a => [a] -> Maybe [a].) It is slightly faster than the previous one.

<lang haskell>import Data.Maybe (fromMaybe) import Control.Monad

bsort :: Ord a => [a] -> [a] bsort s = maybe s bsort $ _bsort s

 where _bsort (x:x2:xs) = if x > x2
           then Just $ x2 : fromMaybe (x:xs) (_bsort $ x:xs)
           else liftM (x:) $ _bsort (x2:xs)
       _bsort _         = Nothing</lang>

HicEst

<lang fortran>SUBROUTINE Bubble_Sort(a)

 REAL :: a(1)

 DO j = LEN(a)-1, 1, -1
   swapped = 0
   DO i = 1, j
     IF (a(i) > a(i+1)) THEN
       temp = a(i)
       a(i) = a(i+1)
       a(i+1) = temp
       swapped = 1
     ENDIF
   ENDDO
   IF (swapped == 0) RETURN
 ENDDO

END</lang>

Icon and Unicon

Icon/Unicon implementation of a bubble sort <lang Icon>procedure main() #: demonstrate various ways to sort a list and string

  demosort(bubblesort,[3, 14, 1, 5, 9, 2, 6, 3],"qwerty")

end

procedure bubblesort(X,op) #: return sorted list local i,swapped

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

  swapped := 1 
  while \swapped := &null do         # the sort
     every  i := 2 to *X do  
        if op(X[i],X[i-1]) then  
           X[i-1] :=: X[swapped := i] 
  return X

end</lang>

Sample output:

Sorting Demo using procedure bubblesort
  on list : [ 3 14 1 5 9 2 6 3 ]
    with op = &null:         [ 1 2 3 3 5 6 9 14 ]   (0 ms)
    with op = "numeric":     [ 1 2 3 3 5 6 9 14 ]   (0 ms)
    with op = "string":      [ 1 14 2 3 3 5 6 9 ]   (0 ms)
    with op = ">>":          [ 9 6 5 3 3 2 14 1 ]   (0 ms)
    with op = ">":           [ 14 9 6 5 3 3 2 1 ]   (0 ms)
    with op = procedure cmp: [ 1 2 3 3 5 6 9 14 ]   (1 ms)
    with op = "cmp":         [ 1 2 3 3 5 6 9 14 ]   (0 ms)
  on string : "qwerty"
    with op = &null:         "eqrtwy"   (0 ms)

The following code supports this and other sorting demonstrations.

Sorting illustrates a difference in the way Icon and Unicon handles data types. Built-in operators for comparing data types make a syntactic distinction between numeric and string types, and sorting structured and user-defined types require custom code. An added complication arises because mixed types are allowed. Two approaches are possible here: (1) that taken by the built-in sort which sorts first by type and then value The sort order of types is: &null, integer, real, string, cset, procedure, list, set, table, and record; and (2) Coercion of types which is used here (and implemented in 'sortop') to decide on using string or numeric sorting. These sorts will not handle more exotic type mixes.
The 'sortop' procedure allows various methods of comparison be selected including customized ones. The example could be made more general to deal with coercion of types like cset to string (admittedly an uninteresting example as csets are already sorted). Custom comparators are shown by and example procedure 'cmp'.
'demosort' can apply different sorting procedures and operators to lists and strings to show how this works. The routines 'displaysort' and 'writex' are helpers.

<lang icon>invocable all # for op

procedure sortop(op,X) #: select how to sort

   op := case op of {               
            "string":  "<<"
            "numeric": "<"
            &null:     if type(!X) == "string" then "<<" else "<"
            default:   op
         }

return proc(op, 2) | runerr(123, image(op)) end

procedure cmp(a,b) #: example custom comparison procedure

   return a < b                      #  Imagine a complex comparison test here!

end

procedure demosort(sortproc,L,s) # demonstrate sort on L and s

   write("Sorting Demo using ",image(sortproc))
   writes("  on list : ")
   writex(L)
   displaysort(sortproc,L)           # default string sort
   displaysort(sortproc,L,"numeric") # explicit numeric sort
   displaysort(sortproc,L,"string")  # explicit string sort
   displaysort(sortproc,L,">>")      # descending string sort
   displaysort(sortproc,L,">")       # descending numeric sort
   displaysort(sortproc,L,cmp)       # ascending custom comparison
   displaysort(sortproc,L,"cmp")     # ascending custom comparison

   writes("  on string : ")
   writex(s)
   displaysort(sortproc,s)           # sort characters in a string
   write()
   return

end

procedure displaysort(sortproc,X,op) #: helper to show sort behavior local t,SX

   writes("    with op = ",left(image(op)||":",15))
   X := copy(X)
   t := &time
   SX := sortproc(X,op)
   writex(SX,"   (",&time - t," ms)")
   return

end

procedure writex(X,suf[]) #: helper for displaysort

   if type(X) == "string" then 
       writes(image(X))
   else {
       writes("[")
       every writes(" ",image(!X))
       writes(" ]")
       }
   every writes(!suf)
   write()

return end</lang>

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.

<lang j>bubbleSort=: (([ (<. , >.) {.@]) , }.@])/^:_</lang>

Test program:

<lang j> ?. 10 $ 10 4 6 8 6 5 8 6 6 6 9

  bubbleSort ?. 10 $ 10

4 5 6 6 6 6 6 8 8 9</lang>

For the most part, bubble sort works against J's strengths. However, once a single pass has been implemented as a list operation, ^:_ tells J to repeat this until the result stops changing.

Java

Bubble sorting (ascending) an array of any Comparable type: <lang java>public static <E extends Comparable<? super E>> void bubbleSort(E[] comparable) {

   boolean changed = false;
   do {
       changed = false;
       for (int a = 0; a < comparable.length - 1; a++) {
           if (comparable[a].compareTo(comparable[a + 1]) > 0) {
               E tmp = comparable[a];
               comparable[a] = comparable[a + 1];
               comparable[a + 1] = tmp;
               changed = true;
           }
       }
   } while (changed);

}</lang>

For descending, simply switch the direction of comparison: <lang java>if (comparable[a].compareTo(comparable[b]) < 0){

  //same swap code as before

}</lang>

JavaScript

<lang javascript>Array.prototype.bubblesort = function() {

   var done = false;
   while (!done) {
       done = true;
       for (var i = 1; i<this.length; i++) {
           if (this[i-1] > this[i]) {
               done = false;
               [this[i-1], this[i]] = [this[i], this[i-1]]
           }
       }
   }
   return this;

}</lang>

Works with: SEE version 3.0

Works with: OSSP js version 1.6.20070208

<lang javascript>Array.prototype.bubblesort = function() {

 var done = false;
 while (! done) {
   done = true;
   for (var i = 1; i < this.length; i++) {
     if (this[i - 1] > this[i]) {
       done = false;
       var tmp = this[i - 1];
       this[i - 1] = this[i];
       this[i] = tmp;
     }
   }
 }
 return this;

}</lang>

Example: <lang javascript>var my_arr = ["G", "F", "C", "A", "B", "E", "D"]; my_arr.bubblesort(); print(my_arr);</lang>

Output:

A,B,C,D,E,F,G

Io

<lang Io> List do(

 bubblesort := method(
   t := true
   while( t,
     t := false
     for( j, 0, self size - 2,
       if( self at( j ) start > self at( j+1 ) start,
         self swapIndices( j,j+1 )
         t := true
       )
     )
   )
   return( self )
 )

) </lang>

Liberty BASIC

   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
   counter = itemCount
   do
       hasChanged = 0
       for i = 1 to counter - 1
           if item(i) > item(i + 1) then
               temp = item(i)
               item(i) = item(i + 1)
               item(i + 1) = temp
               hasChanged = 1
           end if
       next i
       counter =counter -1
   loop while hasChanged = 1
   print "After Sort"
   for i = 1 to itemCount
       print item(i)
   next i

end </lang>

Lisaac

<lang Lisaac>Section Header

+ name := BUBBLE_SORT;

- external := `#include <time.h>`;

Section Public

- main <- (

 + a : ARRAY(INTEGER);

 a := ARRAY(INTEGER).create 0 to 100;
 `srand(time(NULL))`;
 0.to 100 do { i : INTEGER;
   a.put `rand()`:INTEGER to i;
 };

 bubble a;

 a.foreach { item : INTEGER;
   item.print;
   '\n'.print;
 };

);

- bubble a : ARRAY(INTEGER) <- (

 + lower, size, t : INTEGER;
 + sorted : BOOLEAN;
 lower := a.lower;
 size := a.upper - lower + 1;
 {
   sorted := TRUE;
   size := size - 1;
   0.to (size - 1) do { i : INTEGER;
     (a.item(lower + i + 1) < a.item(lower + i)).if {
       t := a.item(lower + i + 1);
       a.put (a.item(lower + i)) to (lower + i + 1);
       a.put t to (lower + i);
       sorted := FALSE;
     };
   };
 }.do_while {!sorted};

);</lang>

Lua

<lang Lua> function bubbleSort(A)

 local itemCount=#A
 local hasChanged
 repeat
   hasChanged = false
   itemCount=itemCount - 1
   for i = 1, itemCount do
     if A[i] > A[i + 1] then
       A[i], A[i + 1] = A[i + 1], A[i]
       hasChanged = true
     end
   end
 until hasChanged == false

end </lang>

Example: <lang lua> list = { 5, 6, 1, 2, 9, 14, 2, 15, 6, 7, 8, 97 } bubbleSort(list) for i, j in pairs(list) do

   print(j)

end </lang>

Lucid

[1] <lang lucid>bsort(a) = if iseod(first a) then a else

             follow(bsort(allbutlast(b)),last(b)) fi
 where
  b = bubble(a);
  bubble(a) = smaller(max, next a)
      where
       max = first a fby larger(max, next a);
       larger(x,y) = if iseod(y) then y elseif x
      end;
  follow(x,y) = if xdone then y upon xdone else x fi
                  where
                     xdone = iseod x fby xdone or iseod x;
                  end;
  last(x) = (x asa iseod next x) fby eod;
  allbutlast(x) = if not iseod(next x) then x else eod fi;
 end</lang>

M4

<lang M4>divert(-1)

define(`randSeed',141592653) define(`setRand',

  `define(`randSeed',ifelse(eval($1<10000),1,`eval(20000-$1)',`$1'))')

define(`rand_t',`eval(randSeed^(randSeed>>13))') define(`random',

  `define(`randSeed',eval((rand_t^(rand_t<<18))&0x7fffffff))randSeed')

define(`set',`define(`$1[$2]',`$3')') define(`get',`defn(`$1[$2]')') define(`new',`set($1,size,0)') dnl for the heap calculations, it's easier if origin is 0, so set value first define(`append',

  `set($1,size,incr(get($1,size)))`'set($1,get($1,size),$2)')

dnl swap(<name>,<j>,<name>[<j>],<k>) using arg stack for the temporary define(`swap',`set($1,$2,get($1,$4))`'set($1,$4,$3)')

define(`deck',

  `new($1)for(`x',1,$2,
        `append(`$1',eval(random%100))')')

define(`show',

  `for(`x',1,get($1,size),`get($1,x) ')')

define(`for',

  `ifelse($#,0,``$0,
  `ifelse(eval($2<=$3),1,
  `pushdef(`$1',$2)$4`'popdef(`$1')$0(`$1',incr($2),$3,`$4')')')')

define(`bubbleonce',

  `for(`x',1,$2,
     `ifelse(eval(get($1,x)>get($1,incr(x))),1,
        `swap($1,x,get($1,x),incr(x))`'1')')0')

define(`bubbleupto',

  `ifelse(bubbleonce($1,$2),0,
     `',
     `bubbleupto($1,decr($2))')')

define(`bubblesort',

  `bubbleupto($1,decr(get($1,size)))')

divert deck(`a',10) show(`a') bubblesort(`a') show(`a')</lang>

Output:

17 63 80 55 90 88 25 9 71 38

9 17 25 38 55 63 71 80 88 90

Mathematica

<lang Mathematica>bubbleSort[{w___, x_, y_, z___}] /; x > y := bubbleSort[{w, y, x, z}] bubbleSort[sortedList_] := sortedList</lang> Example:

bubbleSort[{10, 3, 7, 1, 4, 3, 8, 13, 9}]
{1, 3, 3, 4, 7, 8, 9, 10, 13}

MATLAB

<lang MATLAB>function list = bubbleSort(list)

   hasChanged = true;
   itemCount = numel(list);
   
   while(hasChanged)
       
       hasChanged = false;
       itemCount = itemCount - 1;
       
       for index = (1:itemCount)
 
           if(list(index) > list(index+1))
               list([index index+1]) = list([index+1 index]); %swap
               hasChanged = true;
           end %if
           
       end %for
   end %while

end %bubbleSort</lang>

Sample Output: <lang MATLAB>bubbleSort([5 3 8 4 9 7 6 2 1])

ans =

    1     2     3     4     5     6     7     8     9</lang>

MAXScript

<lang maxscript>fn bubbleSort arr = (

   while true do
   (
       changed = false
       for i in 1 to (arr.count - 1) do
       (
           if arr[i] > arr[i+1] then
           (
               swap arr[i] arr[i+1]
               changed = true
           )
       )
       if not changed then exit
   )
   arr

)</lang>

-- Usage

<lang maxscript>myArr = #(9, 8, 7, 6, 5, 4, 3, 2, 1) myArr = bubbleSort myArr</lang>

MMIX

<lang mmix>Ja IS $127

         LOC Data_Segment

DataSeg GREG @ Array IS @-Data_Segment

         OCTA   999,200,125,1,1020,40,4,5,60,100

ArrayLen IS (@-Array-Data_Segment)/8

NL IS @-Data_Segment BYTE #a,0 LOC @+(8-@)&7

Buffer IS @-Data_Segment

           LOC #1000
           GREG @

sorted IS $5 i IS $6 size IS $1 a IS $0 t IS $20 t1 IS $21 t2 IS $22 % Input: $0 ptr to array, $1 its length (in octabyte) % Trashed: $5, $6, $1, $20, $21, $22 BubbleSort SETL sorted,1 % sorted = true

           SUB   size,size,1       % size--
           SETL  i,0               % i = 0

3H CMP t,i,size % i < size ?

           BNN   t,1F              % if false, end for loop
           8ADDU $12,i,a           % compute addresses of the
           ADDU  t,i,1             % octas a[i] and a[i+1]
           8ADDU $11,t,a
           LDO   t1,$12,0          % get their values
           LDO   t2,$11,0
           CMP   t,t1,t2           % compare
           BN    t,2F              % if t1<t2, next
           STO   t1,$11,0          % else swap them
           STO   t2,$12,0
           SETL  sorted,0          % sorted = false

2H INCL i,1 % i++

           JMP   3B                % next (for loop)

1H PBZ sorted,BubbleSort % while sorted is false, loop

           GO    Ja,Ja,0

% Help function (Print an octabyte) % Input: $0 (the octabyte) BufSize IS 64

           GREG  @

PrintInt8 ADDU t,DataSeg,Buffer % get buffer address

           ADDU  t,t,BufSize       % end of buffer
           SETL  t1,0              % final 0 for Fputs            
           STB   t1,t,0

1H SUB t,t,1 % t--

           DIV   $0,$0,10          % ($0,rR) = divmod($0,10)
           GET   t1,rR             % get reminder
           INCL  t1,'0'            % turn it into ascii digit
           STB   t1,t,0            % store it
           PBNZ  $0,1B             % if $0 /= 0, loop
           OR    $255,t,0          % $255 = t
           TRAP  0,Fputs,StdOut 
           GO    Ja,Ja,0           % print and return

Main ADDU $0,DataSeg,Array % $0 = Array address

           SETL  $1,ArrayLen       % $1 = Array Len
           GO    Ja,BubbleSort     % BubbleSort it
           SETL  $4,ArrayLen       % $4 = ArrayLen

ADDU $3,DataSeg,Array % $3 = Array address 2H BZ $4,1F % if $4 == 0, break

           LDO   $0,$3,0           % $0 = * ($3 + 0)
           GO    Ja,PrintInt8      % print the octa
           ADDU  $255,DataSeg,NL   % add a trailing newline

TRAP 0,Fputs,StdOut

           ADDU  $3,$3,8           % next octa
           SUB   $4,$4,1           % $4--

JMP 2B % loop 1H XOR $255,$255,$255

           TRAP  0,Halt,0          % exit(0)</lang>

Modula-2

<lang modula2>PROCEDURE BubbleSort(VAR a: ARRAY OF INTEGER);

 VAR
   changed:        BOOLEAN;
   temp, count, i: INTEGER;

BEGIN

 count := HIGH(a);
 REPEAT
   changed := FALSE;
   DEC(count);
   FOR i := 0 TO count DO
     IF a[i] > a[i+1] THEN
       temp := a[i];
       a[i] := a[i+1];
       a[i+1] := temp;
       changed := TRUE
     END
   END
 UNTIL NOT changed

END BubbleSort;</lang>

Modula-3

<lang modula3>MODULE Bubble;

PROCEDURE Sort(VAR a: ARRAY OF INTEGER) =

 VAR sorted: BOOLEAN;
     temp, len: INTEGER := LAST(a);
 BEGIN
   WHILE NOT sorted DO
     sorted := TRUE;
     DEC(len);
     FOR i := FIRST(a) TO len DO
       IF a[i+1] < a[i] THEN
         temp := a[i];
         a[i] := a[i + 1];
         a[i + 1] := temp;
         sorted := FALSE;
       END;
     END;
   END;
 END Sort;

END Bubble.</lang>

Nemerle

Functional

<lang Nemerle>using System; using System.Console;

module Bubblesort {

   Bubblesort[T] (x : list[T]) : list[T]
     where T : IComparable
   {
       def isSorted(y)
       {
           |[_] => true
           |y1::y2::ys => (y1.CompareTo(y2) < 0) && isSorted(y2::ys)
       }
       
       def sort(y)
       {
           |[y]        => [y]
           |y1::y2::ys => if (y1.CompareTo(y2) < 0) y1::sort(y2::ys)
                          else y2::sort(y1::ys)
       }
       
       def loop(y)
       {
           if (isSorted(y)) y else {def z = sort(y); loop(z)}            
       }
       
       match(x)
       {
           |[]  => []
           |_   => loop(x)
       }
   }
   
   Main() : void
   {
       def empty = [];
       def single = [2];
       def several = [2, 6, 1, 7, 3, 9, 4];
       WriteLine(Bubblesort(empty));
       WriteLine(Bubblesort(single));
       WriteLine(Bubblesort(several));
   }

}</lang>

Imperative

Translation of: C#

We use an array for this version so that we can update in place. We could use a C# style list (as in the C# example), but that seemed too easy to confuse with a Nemerle style list. <lang Nemerle>using System; using System.Console;

module Bubblesort {

   public static Bubblesort[T](this x : array[T]) : void
     where T : IComparable
   {
       mutable changed = false;
       def ln = x.Length;
       
       do
       {
           changed = false;
           foreach (i in [0 .. (ln - 2)])
           {
               when (x[i].CompareTo(x[i + 1]) > 0)
               {
                   x[i] <-> x[i + 1];
                   changed = true;
               }
           }
       } while (changed);
   }
   
   Main() : void
   {
       def several = array[2, 6, 1, 7, 3, 9, 4];
       several.Bubblesort();
       foreach (i in several)
           Write($"$i  ");
   }

}</lang>

NetRexx

<lang 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 = bubbleSort(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 bubbleSort(list = String[]) public constant binary returns String[]

listLen = list.length loop i_ = 0 to listLen - 1

 loop j_ = i_ + 1 to listLen - 1
   if list[i_].compareTo(list[j_]) > 0 then do
     tmpstor  = list[j_]
     list[j_] = list[i_]
     list[i_] = tmpstor
     end
   end j_
 end i_

return list </lang>

Output

UK  London
US  New York
US  Boston
US  Washington
UK  Washington
US  Birmingham
UK  Birmingham
UK  Boston

Translation of Pseudocode

This version is a direct implementation of this task's pseudocode. <lang 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 = bubbleSort(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 bubbleSort(item = String[]) public constant binary returns String[]

hasChanged = boolean itemCount = item.length loop label h_ until \hasChanged

 hasChanged  = isFalse
 itemCount = itemCount - 1
 loop index = 0 to itemCount - 1
   if item[index].compareTo(item[index + 1]) > 0 then do
     swap            = item[index]
     item[index]     = item[index + 1]
     item[index + 1] = swap
     hasChanged      = isTrue
     end
   end index
 end h_

return item

method isTrue public constant binary returns boolean

 return 1 == 1

method isFalse public constant binary returns boolean

 return \isTrue

</lang>

Objeck

Translation of: C

<lang objeck> function : Swap(p : Int[]) ~ Nil {

 t := p[0];
 p[0] := p[1];
 p[1] := t;

}

function : Sort(a : Int[]) ~ Nil {

 do {
   sorted := true;
   size -= 1;
   for (i:=0; i<a->Size(); i+=1;) {
     if (a[i+1] < a[i]) {
       swap(a+i);
       sorted := 0;
     };
   };
 } 
 while (sorted = false);

} </lang>

OCaml

Like the Haskell versions above:

This version checks for changes in a separate step for simplicity. <lang ocaml>let rec bsort s =

 let rec _bsort = function
   | x :: x2 :: xs when x > x2 ->
       x2 :: _bsort (x :: xs)
   | x :: x2 :: xs ->
       x :: _bsort (x2 :: xs)
   | s -> s
 in
 let t = _bsort s in
   if t = s then t
   else bsort t</lang>

This version uses the polymorphic option type to designate unchanged lists. (The type signature of _bsort is now 'a list -> 'a list option.) It is slightly faster than the previous one. <lang ocaml>let rec bsort s =

 let rec _bsort = function
   | x :: x2 :: xs when x > x2 -> begin
       match _bsort (x :: xs) with
         | None -> Some (x2 :: x :: xs)
         | Some xs2 -> Some (x2 :: xs2)
     end
   | x :: x2 :: xs -> begin
       match _bsort (x2 :: xs) with
         | None -> None
         | Some xs2 -> Some (x :: xs2)
     end
   | _ -> None
 in
   match _bsort s with
     | None -> s
     | Some s2 -> bsort s2</lang>

Octave

<lang octave>function s = bubblesort(v)

 itemCount = length(v);
 do
   hasChanged = false;
   itemCount--;
   for i = 1:itemCount
     if ( v(i) > v(i+1) )

v([i,i+1]) = v([i+1,i]); % swap hasChanged = true;

     endif
   endfor
 until(hasChanged == false)
 s = v;

endfunction</lang>

<lang octave>v = [9,8,7,3,1,100]; disp(bubblesort(v));</lang>

Oz

In-place sorting of mutable arrays: <lang oz>declare

 proc {BubbleSort Arr}
    proc {Swap I J}
       Arr.J := (Arr.I := Arr.J) %% assignment returns the old value
    end
    IsSorted = {NewCell false}
    MaxItem = {NewCell {Array.high Arr}-1}
 in
    for until:@IsSorted do
       IsSorted := true
       for I in {Array.low Arr}..@MaxItem do
          if Arr.I > Arr.(I+1) then
             IsSorted := false
             {Swap I I+1}
          end
       end
       MaxItem := @MaxItem - 1
    end
 end
 Arr = {Tuple.toArray unit(10 9 8 7 6 5 4 3 2 1)}

in

 {BubbleSort Arr}
 {Inspect Arr}</lang>

Purely-functional sorting of immutable lists: <lang oz>declare

 local
    fun {Loop Xs Changed ?IsSorted}
       case Xs
       of X1|X2|Xr andthen X1 > X2 then
          X2|{Loop X1|Xr true IsSorted}
       [] X|Xr then
          X|{Loop Xr Changed IsSorted}
       [] nil then
          IsSorted = {Not Changed}
          nil
       end
    end
 in
    fun {BubbleSort Xs}
       IsSorted
       Result = {Loop Xs false ?IsSorted}
    in
       if IsSorted then Result
       else {BubbleSort Result}
       end
    end
 end

in

 {Show {BubbleSort [3 1 4 1 5 9 2 6 5]}}</lang>

PARI/GP

<lang parigp>bubbleSort(v)={

 for(i=1,#v-1,
   for(j=i+1,#v,
     if(v[j]<v[i],
       my(t=v[j]);
       v[j]=v[i];
       v[i]=t
     )
   )
 );
 v

};</lang>

Pascal

<lang pascal>procedure bubble_sort(n: integer; var list: array of real); var

 i, j: integer;
 t: real;

begin

 for i := n downto 2 do
    for j := 0 to i - 1 do
    begin
        if list[j] < list[j + 1] then
          continue;
        t := list[j];
        list[j] := list[j + 1];
        list[j + 1] := t;
    end;

end;</lang>

Usage:<lang pascal> var

 list: array[0 .. 9] of real;

// ... bubble_sort(9, list); </lang>

Perl

<lang perl># Sorts an array in place sub bubble_sort {

   for my $i (0 .. $#_){
       for my $j ($i + 1 .. $#_){
           $_[$j] < $_[$i] and @_[$i, $j] = @_[$j, $i];
       }
   }

}</lang>

Usage:

<lang perl>my @a = (39, 25, 30, 28, 36, 72, 98, 25, 43, 38); bubble_sort(@a);</lang>

Perl 6

Works with: Rakudo version #24 "Seoul"

<lang perl6>sub bubble_sort (@a is rw) {

   for ^@a -> $i {
       for $i ^..^ @a -> $j {
           @a[$j] < @a[$i] and @a[$i, $j] = @a[$j, $i];
       }
   }

}</lang>

PHP

<lang php>function bubbleSort( array &$array ) { do { $swapped = false; for( $i = 0, $c = count( $array ) - 1; $i < $c; $i++ ) { if( $array[$i] > $array[$i + 1] ) { list( $array[$i + 1], $array[$i] ) = array( $array[$i], $array[$i + 1] ); $swapped = true; } } } while( $swapped ); }</lang>

PL/I

<lang PL/I> /* A primitive bubble sort */ bubble_sort: procedure (A);

  declare A(*) fixed binary;
  declare temp fixed binary;
  declare i fixed binary, no_more_swaps bit (1) aligned;

  do until (no_more_swaps);
     no_more_swaps = true;
     do i = lbound(A,1) to hbound(A,1)-1;
        if A(i) > A(i+1) then
           do; temp = A(i); A(i) = A(i+1); A(i+1) = temp;
               no_more_swaps = false;
           end;
     end;
  end;

end bubble_sort; </lang>

PicoLisp

<lang PicoLisp>(de bubbleSort (Lst)

  (use Chg
     (loop
        (off Chg)
        (for (L Lst (cdr L) (cdr L))
           (when (> (car L) (cadr L))
              (xchg L (cdr L))
              (on Chg) ) )
        (NIL Chg Lst) ) ) )</lang>

Pop11

<lang pop11>define bubble_sort(v); lvars n=length(v), done=false, i; while not(done) do

  true -> done;
  n - 1 -> n;
  for i from 1 to n do
     if v(i) > v(i+1) then
        false -> done;
        ;;; Swap using multiple assignment
        (v(i+1), v(i)) -> (v(i), v(i+1));
     endif;
  endfor;

endwhile; enddefine;

Test it

vars ar = { 10 8 6 4 2 1 3 5 7 9}; bubble_sort(ar); ar =></lang>

PostScript

<lang PostScript> /bubblesort{ /x exch def /temp x x length 1 sub get def /i x length 1 sub def /j i 1 sub def

x length 1 sub{ i 1 sub{ x j 1 sub get x j get lt { /temp x j 1 sub get def x j 1 sub x j get put x j temp put }if /j j 1 sub def }repeat /i i 1 sub def /j i 1 sub def }repeat x pstack }def </lang>

PowerShell

<lang powershell>function bubblesort ($a) {

   $l = $a.Length
   $hasChanged = $true
   while ($hasChanged) {
       $hasChanged = $false
       $l--
       for ($i = 0; $i -lt $l; $i++) {
           if ($a[$i] -gt $a[$i+1]) {
               $a[$i], $a[$i+1] = $a[$i+1], $a[$i]
               $hasChanged = $true
           }
       }
   }

}</lang>

PureBasic

<lang PureBasic>Procedure bubbleSort(Array a(1))

 Protected i, itemCount, hasChanged
 
 itemCount = ArraySize(a())
 Repeat
   hasChanged = #False
   itemCount - 1
   For i = 0 To itemCount
     If a(i) > a(i + 1)
       Swap a(i), a(i + 1)
       hasChanged = #True
     EndIf 
   Next  
 Until hasChanged = #False

EndProcedure</lang>

Python

<lang python>def bubble_sort(seq):

   """Inefficiently sort the mutable sequence (list) in place.
      seq MUST BE A MUTABLE SEQUENCE.

      As with list.sort() and random.shuffle this does NOT return 
   """
   changed = True
   while changed:
       changed = False
       for i in xrange(len(seq) - 1):
           if seq[i] > seq[i+1]:
               seq[i], seq[i+1] = seq[i+1], seq[i]
               changed = True
   return None

if __name__ == "__main__":

  """Sample usage and simple test suite"""

  from random import shuffle

  testset = range(100)
  testcase = testset[:] # make a copy
  shuffle(testcase)
  assert testcase != testset  # we've shuffled it
  bubble_sort(testcase)
  assert testcase == testset  # we've unshuffled it back into a copy</lang>

Qi

<lang Qi>(define bubble-shot

 [A]     -> [A]
 [A B|R] -> [B|(bubble-shot [A|R])] where (> A B)
 [A  |R] -> [A|(bubble-shot R)])

(define bubble-sort

 X -> (fix bubble-shot X))

(bubble-sort [6 8 5 9 3 2 2 1 4 7]) </lang>

R

<lang R>bubblesort <- function(v) {

 itemCount <- length(v)
 repeat {
   hasChanged <- FALSE
   itemCount <- itemCount - 1
   for(i in 1:itemCount) {
     if ( v[i] > v[i+1] ) {
       t <- v[i]
       v[i] <- v[i+1]
       v[i+1] <- t
       hasChanged <- TRUE
     }
   }
   if ( !hasChanged ) break;
 }
 v

}

v <- c(9,8,7,3,1,100) print(bubblesort(v))</lang>

REXX

<lang rexx> /*REXX program sorts an array using the bubble-sort method. */

call gen@ /*generate array elements. */ call show@ 'before sort' /*show before array elements*/ call bubbleSort highItem /*invoke the bubble sort. */ call show@ ' after sort' /*show after array elements*/ exit

/*─────────────────────────────────────BUBBLESORT subroutine───────*/ bubbleSort: procedure expose @.; parse arg n /*n=number of items.*/

                                      /*diminish #items each time.*/
 do until done                        /*sort until it's done.     */
 done=1                               /*assume it's done (1=true).*/

   do j=1 for n-1                     /*sort  M  items this time. */
   k=j+1                              /*point to next item.       */
   if @.j>@.k then do                 /*out of order ?            */
                   _=@.j              /*assign to a temp variable.*/
                   @.j=@.k            /*swap current with next.   */
                   @.k=_              /*... and next with _       */
                   done=0             /*indicate it's not done.   */
                   end                /*   1=true    0=false      */
   end

end

return

/*─────────────────────────────────────GEN@ subroutine─────────────*/ gen@: @.= /*assign default value. */

@.1 ='---letters of the Hebrew alphabet---' @.2 ='====================================' @.3 ='aleph [alef]' @.4 ='beth [bet]' @.5 ='gimel' @.6 ='daleth [dalet]' @.7 ='he' @.8 ='waw [vav]' @.9 ='zayin' @.10='heth [het]' @.11='teth [tet]' @.12='yod' @.13='kaph [kaf]' @.14='lamed' @.15='mem' @.16='nun' @.17='samekh' @.18='ayin' @.19='pe' @.20='sadhe [tsadi]' @.21='qoph [qof]' @.22='resh' @.23='shin' @.24='taw [tav]'

 do highItem=1 while @.highItem\==  /*find how many entries.    */
 end

highItem=highItem-1 /*adjust highItem slightly. */ return

/*─────────────────────────────────────SHOW@ subroutine────────────*/ show@: widthH=length(highItem) /*maximum width of any line.*/

 do j=1 for highItem
 say 'element' right(j,widthH) arg(1)':' @.j
 end

say copies('─',80) /*show a seperator line. */ return </lang> Output:

element  1 before sort: ---letters of the Hebrew alphabet---
element  2 before sort: ====================================
element  3 before sort: aleph   [alef]
element  4 before sort: beth    [bet]
element  5 before sort: gimel
element  6 before sort: daleth  [dalet]
element  7 before sort: he
element  8 before sort: waw     [vav]
element  9 before sort: zayin
element 10 before sort: heth    [het]
element 11 before sort: teth    [tet]
element 12 before sort: yod
element 13 before sort: kaph    [kaf]
element 14 before sort: lamed
element 15 before sort: mem
element 16 before sort: nun
element 17 before sort: samekh
element 18 before sort: ayin
element 19 before sort: pe
element 20 before sort: sadhe   [tsadi]
element 21 before sort: qoph    [qof]
element 22 before sort: resh
element 23 before sort: shin
element 24 before sort: taw     [tav]
────────────────────────────────────────────────────────────────────────────────
element  1  after sort: ---letters of the Hebrew alphabet---
element  2  after sort: ====================================
element  3  after sort: aleph   [alef]
element  4  after sort: ayin
element  5  after sort: beth    [bet]
element  6  after sort: daleth  [dalet]
element  7  after sort: gimel
element  8  after sort: he
element  9  after sort: heth    [het]
element 10  after sort: kaph    [kaf]
element 11  after sort: lamed
element 12  after sort: mem
element 13  after sort: nun
element 14  after sort: pe
element 15  after sort: qoph    [qof]
element 16  after sort: resh
element 17  after sort: sadhe   [tsadi]
element 18  after sort: samekh
element 19  after sort: shin
element 20  after sort: taw     [tav]
element 21  after sort: teth    [tet]
element 22  after sort: waw     [vav]
element 23  after sort: yod
element 24  after sort: zayin
────────────────────────────────────────────────────────────────────────────────

Ruby

Generally, this task should be accomplished in Ruby using Array.sort!. Here we take an approach that's more comparable with the other examples on this page.

This example adds the bubblesort! method to the Array object. Below are two different methods that show four different iterating constructs in ruby.

<lang ruby>class Array

 def bubblesort1!
   length.times do |j|
     for i in 1...(length - j)
       if self[i] < self[i - 1]
         self[i], self[i - 1] = self[i - 1], self[i]
       end
     end
   end
   self
 end
  def bubblesort2!
   each_index do |index|
     (length - 1).downto( index ) do |i|
       self[i-1], self[i] = self[i], self[i-1] if self[i-1] < self[i]
     end
   end
   self
 end

end ary = [3, 78, 4, 23, 6, 8, 6] ary.bubblesort1! p ary

=> [3, 4, 6, 6, 8, 23, 78]</lang>

Sather

<lang sather>class SORT{T < $IS_LT{T}} is

 private swap(inout a, inout b:T) is
   temp ::= a;
   a := b;
   b := temp;
 end;
 bubble_sort(inout a:ARRAY{T}) is
   i:INT;
   if a.size < 2 then return; end;
   loop
     sorted ::= true;
     loop i := 0.upto!(a.size - 2);
       if a[i+1] < a[i] then
         swap(inout a[i+1], inout a[i]);
         sorted := false;
       end;
     end;
     until!(sorted);
   end;
 end;

end;</lang>

<lang sather>class MAIN is

 main is
   a:ARRAY{INT} := |10, 9, 8, 7, 6, -10, 5, 4|;
   SORT{INT}::bubble_sort(inout a);
   #OUT + a + "\n";
 end;

end;</lang>

This should be able to sort (in ascending order) any object for which is_lt (less than) is defined.

Scala

This slightly more complex version of Bubble Sort avoids errors with indices.

<lang scala>def bubbleSort[T](arr: Array[T])(implicit o: Ordering[T]) {

 import o._
 val consecutiveIndices = (arr.indices, arr.indices drop 1).zipped
 var hasChanged = true
 do {
   hasChanged = false
   consecutiveIndices foreach { (i1, i2) =>
     if (arr(i1) > arr(i2)) {
       hasChanged = true
       val tmp = arr(i1)
       arr(i1) = arr(i2)
       arr(i2) = tmp
     }
   }
 } while(hasChanged)

}</lang>

Scheme

<lang scheme>(define (bubble-sort x gt?)

 (letrec
   ((fix (lambda (f i)
      (if (equal? i (f i))
          i
          (fix f (f i)))))

    (sort-step (lambda (l)
       (if (or (null? l) (null? (cdr l)))
           l
           (if (gt? (car l) (cadr l))
               (cons (cadr l) (sort-step (cons (car l) (cddr l))))
               (cons (car  l) (sort-step (cdr l))))))))

 (fix sort-step x)))</lang>

This solution recursively finds the fixed point of sort-step. A comparison function must be passed to bubblesort. Example usages: <lang scheme>(bubble-sort (list 1 3 5 9 8 6 4 2) >) (bubble-sort (string->list "Monkey") char<?)</lang>

Here is the same function, using a different syntax:

<lang scheme>(define (bsort l gt?)

 (define (dosort l)
   (cond ((null? (cdr l))
          l)
         ((gt? (car l) (cadr l))
          (cons (cadr l) (dosort (cons (car l) (cddr l)))))
         (else 
          (cons (car l) (dosort (cdr l))))))
 (let ((try (dosort l)))
   (if (equal? l try)
       l
       (bsort try gt?))))

</lang> For example, you could do <lang scheme>(bsort > '(2 4 6 2)) (1 2 3)</lang>

Seed7

<lang seed7>const proc: bubbleSort (inout array elemType: arr) is func

 local
   var boolean: swapped is FALSE;
   var integer: i is 0;
   var elemType: help is elemType.value;
 begin
   repeat
     swapped := FALSE;
     for i range 1 to length(arr) - 1 do
       if arr[i] > arr[i + 1] then
         help := arr[i];
         arr[i] := arr[i + 1];
         arr[i + 1] := help;
         swapped := TRUE;
       end if;
     end for;
   until not swapped;
 end func;</lang>

Original source: [2]

Smalltalk

A straight translation from the pseudocode above. Swap is done with a block closure.

<lang smalltalk>|item swap itemCount hasChanged| item := #(1 4 5 6 10 8 7 61 0 -3) copy. swap := [:indexOne :indexTwo| |temp| temp := item at: indexOne. item at: indexOne put: (item at: indexTwo). item at: indexTwo put: temp].

itemCount := item size. [hasChanged := false. itemCount := itemCount - 1. 1 to: itemCount do: [:index | (item at: index) > (item at: index + 1) ifTrue: [swap value: index value: index + 1. hasChanged := true]]. hasChanged] whileTrue.</lang>

SNOBOL4

<lang SNOBOL4>* # Sort array in place, return array

       define('bubble(a,alen)i,j,ub,tmp') :(bubble_end)

bubble i = 1; ub = alen outer gt(ub,1) :f(bdone)

       j = 1

inner le(a<j>, a<j + 1>) :s(incrj)

       tmp = a<j>
       a<j> = a<j + 1>
       a<j + 1> = tmp

incrj j = lt(j + 1,ub) j + 1 :s(inner)

       ub = ub - 1 :(outer)

bdone bubble = a :(return) bubble_end

# Fill array with test data

       str = '33 99 15 54 1 20 88 47 68 72'
       output = str; arr = array(10)

floop i = i + 1; str span('0123456789') . arr = :s(floop)

# Test and display
bubble(arr,10); str =
sloop j = j + 1; str = str arr<j> ' ' :s(sloop)
output = trim(str)
end</lang>
Output:
33 99 15 54 1 20 88 47 68 72 1 15 20 33 47 54 68 72 88 99
SPARK
Works with: SPARK GPL version 2010
The first version is based on the Ada version, with Integer for both the array index and the array element.
Static analysis of this code shows that it is guaranteed free of any run-time error when called from any other SPARK code. <lang Ada>package Bubble is
type Arr is array(Integer range <>) of Integer;
procedure Sort (A : in out Arr); --# derives A from *;
end Bubble;

package body Bubble is
procedure Sort (A : in out Arr) is Finished : Boolean; Temp : Integer; begin if A'Last /= A'First then loop Finished := True; for J in Integer range A'First .. A'Last - 1 loop if A (J + 1) < A (J) then Finished := False; Temp := A (J + 1); A (J + 1) := A (J); A (J) := Temp; end if; end loop; --# assert A'Last /= A'First; exit when Finished; end loop; end if; end Sort;
end Bubble; </lang> The next version has a postcondition to guarantee that the returned array is sorted correctly. This requires the two proof rules that follow the source. The Ada code is identical with the first version. <lang Ada>package Bubble is
type Arr is array(Integer range <>) of Integer;
-- Sorted is a proof function with the definition: -- Sorted(A, From_I, To_I) -- <-> -- (for all I in Integer range From_I .. To_I - 1 => -- (A(I) <= A(I + 1))) . -- --# function Sorted (A : Arr; --# From_I, To_I : Integer) return Boolean; procedure Sort (A : in out Arr); --# derives A from *; --# post Sorted(A, A'First, A'Last);
end Bubble;

package body Bubble is
procedure Sort (A : in out Arr) is Finished : Boolean; Temp : Integer; begin if A'Last > A'First then loop Finished := True; for J in Integer range A'First .. A'Last - 1 --# assert Finished -> Sorted(A, A'First, J); loop if A (J + 1) < A (J) then Finished := False; Temp := A (J + 1); A (J + 1) := A (J); A (J) := Temp; end if; end loop; --# assert A'Last /= A'First --# and (Finished -> Sorted(A, A'First, A'Last)); exit when Finished; end loop; end if; end Sort;
end Bubble; </lang> The proof rules are stated here without justification (but they are fairly obvious). A formal proof of these rules from the definition of Sorted has been completed.
bubble_sort_rule(1): sorted(A, I, J) may_be_deduced_from [ J <= I ] . bubble_sort_rule(2): Fin -> sorted(A, I, J + 1) may_be_deduced_from [ Fin -> sorted(A, I, J), element(A, [J]) <= element(A, [J + 1]) ] .
Both of the two versions above use an inner loop that scans over all the array on every pass of the outer loop. This makes the proof in the second version very simple.
The final version scans over a reducing portion of the array in the inner loop, consequently the proof becomes more complex. The package specification for this version is the same as the second version above. The package body defines two more proof functions. <lang Ada>package body Bubble is
procedure Sort (A : in out Arr) is Finished : Boolean;
-- In_Position is a proof function with the definition: -- In_Position(A, A_Start, A_I, A_End) -- <-> -- ((for all K in Integer range A_Start .. A_I - 1 => -- (A(K) <= A(A_I))) -- and -- Sorted(A, A_I, A_End) . -- --# function In_Position (A : Arr; --# A_Start, A_I, A_End : Integer) return Boolean;
-- Swapped is a proof function with the definition: -- Swapped(A_In, A_Out, I1, I2) -- <-> -- (A_Out = A_In[I1 => A_In(I2); I2 => A_In(I1)]). -- --# function Swapped (A_In, A_Out : Arr; --# I1, I2 : Integer) return Boolean;
procedure Swap (A : in out Arr; I1 : in Integer; I2 : in Integer) --# derives A from *, I1, I2; --# pre I1 in A'First .. A'Last --# and I2 in A'First .. A'Last; --# post Swapped(A~, A, I1, I2); is Temp : Integer; begin Temp := A(I2); A(I2) := A(I1); A(I1) := Temp; end Swap; pragma Inline (Swap);
begin if A'Last > A'First then for I in reverse Integer range A'First + 1 .. A'Last loop Finished := True; for J in Integer range A'First .. I - 1 loop if A (J + 1) < A (J) then Finished := False; Swap (A, J, J + 1); end if; --# assert I% = I -- I is unchanged by execution of the loop --# and (for all K in Integer range A'First .. J => --# (A(K) <= A(J + 1))) --# and (I < A'Last -> In_Position(A, A'First, I + 1, A'Last)) --# and (Finished -> Sorted(A, A'First, J + 1)); end loop; exit when Finished; --# assert In_Position(A, A'First, I, A'Last); end loop; end if; end Sort;
end Bubble; </lang> Completion of the proof of this version requires more rules than the previous version and they are rather more complex. Creation of these rules is quite straightforward - I tend to write whatever rules the Simplifier needs first and then validate them afterwards. A formal proof of these rules from the definition of Sorted, In_Position and Swapped has been completed.
bubble_sort_rule(1): sorted(A, I, J) may_be_deduced_from [ J <= I ] . bubble_sort_rule(2): sorted(A, I - 1, J) may_be_deduced_from [ sorted(A, I, J), element(A, [I - 1]) <= element(A, [I]) ] . bubble_sort_rule(3): Fin -> sorted(A, I, J + 1) may_be_deduced_from [ Fin -> sorted(A, I, J), element(A, [J]) <= element(A, [J + 1]) ] . bubble_sort_rule(4): sorted(A, Fst, Lst) may_be_deduced_from [ sorted(A, Fst, I), I < Lst -> in_position(A, Fst, I + 1, Lst), I <= Lst ] . bubble_sort_rule(5): in_position(A, Fst, I, Lst) may_be_deduced_from [ I < Lst -> in_position(A, Fst, I + 1, Lst), for_all(K : integer, Fst <= K and K <= I - 1 -> element(A, [K]) <= element(A, [I])), I >= Fst, I <= Lst ] . bubble_sort_rule(6): I < Lst -> in_position(A2, Fst, I + 1, Lst) may_be_deduced_from [ I < Lst -> in_position(A1, Fst, I + 1, Lst), swapped(A1, A2, J + 1, J + 2), J + 2 < I + 1, J >= Fst ] . bubble_sort_rule(7): I - 1 < Lst -> in_position(A2, Fst, I, Lst) may_be_deduced_from [ in_position(A1, Fst, I, Lst), swapped(A1, A2, J, J + 1), J + 1 < I, J >= Fst ] . bubble_sort_rule(8): for_all(K : integer, I <= K and K <= I -> element(A, [K]) <= element(A, [I + 1])) may_be_deduced_from [ element(A, [I]) <= element(A, [I + 1]) ] . bubble_sort_rule(9): for_all(K : integer, I <= K and K <= I -> element(A2, [K]) <= element(A2, [I + 1])) may_be_deduced_from [ element(A1, [I]) > element(A1, [I + 1]), swapped(A1, A2, I, I + 1) ] . bubble_sort_rule(10): for_all(K2 : integer, Fst <= K2 and K2 <= J + 1 -> element(A, [K2]) <= element(A, [J + 2])) may_be_deduced_from [ for_all(K1 : integer, Fst <= K1 and K1 <= J -> element(A, [K1]) <= element(A, [J + 1])), element(A, [J + 1]) <= element(A, [J + 2]) ] . bubble_sort_rule(11): for_all(K2 : integer, Fst <= K2 and K2 <= J + 1 -> element(A2, [K2]) <= element(A2, [J + 2])) may_be_deduced_from [ for_all(K1 : integer, Fst <= K1 and K1 <= J -> element(A1, [K1]) <= element(A1, [J + 1])), element(A1, [J + 1]) > element(A1, [J + 2]), swapped(A1, A2, J + 1, J + 2) ] .
TI-83 BASIC
Input your data into L₁ and run this program to organize it.
:L₁→L₂ :1+dim(L₂ :For(D,1,dim(L₂) :N-1→N :0→I :For(C,1,dim(L₂-2) :For(A,dim(L₂)-N+1,dim(L₂)-1) :If L₂(A)>L₂(A_1) :Then :1→I :L₂(A)→B :L₂(A+1)→L₂(A) :B→L₂(A+1) :End :End :End :If I=0 :Goto C :End :Lbl C :If L₂(1)>L₂(2) :Then :L₂(1)→B :L₂(2)→L₂(1) :B→L₂(2) :End :DelVar A :DelVar B :DelVar C :DelVar D :DelVar N :DelVar I :Return
Odd-Even Bubble Sort (same IO):
:"ODD-EVEN" :L₁→L₂( :1+dim(L₂)→N :For(D,1,dim(L₂)) :N-1→N :0→O :For(C,1,dim(L₂)-2) :For(A,dim(L₂)-N+2,dim(L₂)-1,2) :If L₂(A)>L₂(A+1) :Then :1→O :L₂(A)→B :L₂(A+1)→L₂(A) :B→L₂(A+1) :End :End :For(A,dim(L₂)-N+1,dim(L₂)-1,2) :If L₂(A)>L₂(A+1) :Then :1→O :L₂(A)→B :L₂(A+1)→L₂(A) :B→L₂(A+1) :End :End :End :If O=0 :Goto C :End :Lbl C :If L₂(1)>L₂(2) :Then :L₂(1)→B :L₂(2)→L₂(1) :B→L₂(2) :End :DelVar A :DelVar B :DelVar C :DelVar D :DelVar N :DelVar O :Return
Tcl
Library: Tcllib (Package: struct::list)
<lang tcl>package require Tcl 8.5 package require struct::list
proc bubblesort {A} {
set len [llength $A] set swapped true while {$swapped} { set swapped false for {set i 0} {$i < $len - 1} {incr i} { set j [expr {$i + 1}] if {[lindex $A $i] > [lindex $A $j]} { struct::list swap A $i $j set swapped true } } incr len -1 } return $A
}
puts [bubblesort {8 6 4 2 1 3 5 7 9}] ;# => 1 2 3 4 5 6 7 8 9</lang>
Idiomatic code uses the builtin lsort instead, which is a stable O(n log n) sort.
Toka
Toka does not have a bubble sort predefined, but it is easy to code a simple one:
<lang toka>#! A simple Bubble Sort function value| array count changed | [ ( address count -- )
to count to array count 0 [ count 0 [ i array array.get i 1 + array array.get 2dup > [ i array array.put i 1 + array array.put ] [ 2drop ] ifTrueFalse ] countedLoop count 1 - to count ] countedLoop
] is bsort
! Code to display an array
[ ( array count -- )
0 swap [ dup i swap array.get . ] countedLoop drop cr
] is .array
! Create a 10-cell array
10 cells is-array foo
! Fill it with random values
20 1 foo array.put 50 2 foo array.put 650 3 foo array.put 120 4 foo array.put 110 5 foo array.put 101 6 foo array.put
1321 7 foo array.put 1310 8 foo array.put
987 9 foo array.put 10 10 foo array.put
! Display the array, sort it, and display it again
foo 10 .array foo 10 bsort foo 10 .array</lang>
Unicon
See Icon.
UnixPipes
<lang bash>rm -f _sortpass
reset() {
test -f _tosort || mv _sortpass _tosort
}
bpass() {
(read a; read b test -n "$b" -a "$a" && ( test $a -gt $b && (reset; echo $b; (echo $a ; cat) | bpass ) || (echo $a; (echo $b ; cat) | bpass ) ) || echo $a)
}
bubblesort() {
cat > _tosort while test -f _tosort do cat _tosort | (rm _tosort;cat) |bpass > _sortpass done cat _sortpass
}
cat to.sort | bubblesort</lang>
Ursala
The bubblesort function is parameterized by a relational predicate. <lang Ursala>#import nat
bubblesort "p" = @iNX ^=T ^llPrEZryPrzPlrPCXlQ/~& @l ~&aitB^?\~&a "p"?ahthPX/~&ahPfatPRC ~&ath2fahttPCPRC
cast %nL
example = bubblesort(nleq) <362,212,449,270,677,247,567,532,140,315></lang> output:
<140,212,247,270,315,362,449,532,567,677>
VBScript
Doing the decr and incr thing is superfluous, really. I just had stumbled over the byref thing for swap and wanted to see where else it would work.
For those unfamiliar with Perth, WA Australia, the five strings being sorted are names of highways.
Implementation
<lang vb> sub decr( byref n ) n = n - 1 end sub
sub incr( byref n ) n = n + 1 end sub
sub swap( byref a, byref b) dim tmp tmp = a a = b b = tmp end sub
function bubbleSort( a ) dim changed dim itemCount itemCount = ubound(a) do changed = false decr itemCount for i = 0 to itemCount if a(i) > a(i+1) then swap a(i), a(i+1) changed = true end if next loop until not changed bubbleSort = a end function </lang>
Invocation
<lang vb> dim a a = array( "great eastern", "roe", "stirling", "albany", "leach") wscript.echo join(a,", ") bubbleSort a wscript.echo join(a,", ") </lang>
Output
great eastern, roe, stirling, albany, leach albany, great eastern, leach, roe, stirling
Visual Basic .NET
Platform: .NET
Works with: Visual Basic .NET version 9.0+
<lang vbnet>Do Until NoMoreSwaps = True
NoMoreSwaps = True For Counter = 1 To (NumberOfItems - 1) If List(Counter) > List(Counter + 1) Then NoMoreSwaps = False Temp = List(Counter) List(Counter) = List(Counter + 1) List(Counter + 1) = Temp End If Next NumberOfItems = NumberOfItems - 1
Loop</lang>
Yorick
<lang yorick>func bubblesort(&items) {
itemCount = numberof(items); do { hasChanged = 0; itemCount--; for(index = 1; index <= itemCount; index++) { if(items(index) > items(index+1)) { items([index,index+1]) = items([index+1,index]); hasChanged = 1; } } } while(hasChanged);
}</lang>