# Sorting numbers using bubble sort technique in php (Sorting Code)?

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## Bubble sort

A bubble sort, a sorting algorithm that continuously steps through a list, swapping items until they appear in the correct order. Bubble sort is a simple sorting algorithm. The algorithm starts at the beginning of the data set. It compares the first two elements, and if the first is greater than the second, it swaps them. It continues doing this for each pair of adjacent elements to the end of the data set. It then starts again with the first two elements, repeating until no swaps have occurred on the last pass. This algorithm's average and worst case performance is O(n2), so it is rarely used to sort large, unordered, data sets. Bubble sort can be used to sort a small number of items (where its inefficiency is not a high penalty). Bubble sort may also be efficiently used on a list that is already sorted except for a very small number of elements. For example, if only one element is not in order, bubble sort will take only 2n time. If two elements are not in order, bubble sort will take only at most 3n time...

<?php
$num=array(1,9,3,7,8,2,5,6); function sorter($num)
{
for ($i=0;$i<=count($num)-1;$i++)
{
if($num[$i]>$num[$i+1])
{
//echo $num[$i].':'.$num[$i+1].'<br>';
$temp=$num[$i];$num[$i]=$num[$i+1];$num[$i+1]=$temp;
$num=sorter($num);
}
}
return $num; } var_dump($num);
var_dump(sorter(\$num));
?>
posted Aug 22, 2014

## Related Articles

Bubble sort is a simple sorting algorithm that works by repeatedly stepping through the list to be sorted, comparing each pair of adjacent items and swapping them if they are in the wrong order. The pass through the list is repeated until no swaps are needed, which indicates that the list is sorted. The algorithm gets its name from the way smaller elements "bubble" to the top of the list. Because it only uses comparisons to operate on elements, it is a comparison sort. Although the algorithm is simple, most of the other sorting algorithms are more efficient for large lists. Bubble sort is not a stable sort which means that if two same elements are there in the list, they may not get their same order with respect to each other.

Step-by-step example:
Let us take the array of numbers "5 1 4 2 8", and sort the array from lowest number to greatest number using bubble sort. In each step, elements written in bold are being compared. Three passes will be required.
*First Pass:*

( 5 1 4 2 8 ) \to ( 1 5 4 2 8 ), Here, algorithm compares the first two elements, and swaps since 5 > 1.
( 1 5 4 2 8 ) \to ( 1 4 5 2 8 ), Swap since 5 > 4
( 1 4 5 2 8 ) \to
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( 1 4 2 5 8 ), Swap since 5 > 2
( 1 4 2 5 8 ) \to ( 1 4 2 5 8 ), Now, since these elements are already in order (8 > 5), algorithm does not swap them.


Second Pass:

( 1 4 2 5 8 ) \to ( 1 4 2 5 8 )
( 1 4 2 5 8 ) \to ( 1 2 4 5 8 ), Swap since 4 > 2
( 1 2 4 5 8 ) \to ( 1 2 4 5 8 )
( 1 2 4 5 8 ) \to ( 1 2 4 5 8 )
Now, the array is already sorted, but our algorithm does not know if it is completed. The algorithm needs one whole pass without any swap to know it is sorted.


Third Pass:

( 1 2 4 5 8 ) \to ( 1 2 4 5 8 )
( 1 2 4 5 8 ) \to ( 1 2 4 5 8 )
( 1 2 4 5 8 ) \to ( 1 2 4 5 8 )
( 1 2 4 5 8 ) \to ( 1 2 4 5 8 )


Algorithm For Bubble Sort:

Step 1: Repeat Steps 2 and 3 for i=1 to 10

Step 2: Set j=1

Step 3: Repeat while j<=n

(A) if  a[i] < a[j]

Then interchange a[i] and a[j]

[End of if]

(B) Set j = j+1
[End of Inner Loop]

[End of Step 1 Outer Loop]

Step 4: Exit


Optimized Algorithm For Bubble Sort:

procedure bubbleSort ( A : list of sortable items )
n = length(A)
repeat
swapped = false
for i = 1 to n-1 inclusive do
if A[i-1] > A[i] then
swap(A[i-1], A[i])
swapped = true
end if
end for
n = n - 1
until not swapped
end procedure


Bubble Sort Program using Function:

#include <stdio.h>

void bubble_sort(long [], long);

int main()
{
long array[100], n, c, d, swap;

printf("Enter number of elements\n");
scanf("%ld", &n);

printf("Enter %ld integers\n", n);

for (c = 0; c < n; c++)
scanf("%ld", &array[c]);

bubble_sort(array, n);

printf("Sorted list in ascending order:\n");

for ( c = 0 ; c < n ; c++ )
printf("%ld\n", array[c]);

return 0;
}

void bubble_sort(long list[], long n)
{
long c, d, t;

for (c = 0 ; c < ( n - 1 ); c++)
{
for (d = 0 ; d < n - c - 1; d++)
{
if (list[d] > list[d+1])
{
/* Swapping */

t         = list[d];
list[d]   = list[d+1];
list[d+1] = t;
}
}
}
}