Write a program to implement sorting with Quick sort using Divide & Conquer method.

#include <stdio.h>

int split ( int*, int, int ) ;

void main( )

{

          int arr[10] = { 11, 2, 9, 13, 57, 25, 17, 1, 90, 3 } ;

          int i ;

void quicksort ( int *, int, int ) ;

quicksort ( arr, 0, 9 ) ;

printf ( "\nArray after sorting:\n") ;

for ( i = 0 ; i <= 9 ; i++ )

          printf ( "%d\t", arr[i] ) ;

}

void quicksort ( int a[ ], int lower, int upper )

{

          int i ;

          if ( upper > lower )

          {

                   i = split ( a, lower, upper ) ;

                   quicksort ( a, lower, i - 1 ) ;

                   quicksort ( a, i + 1, upper ) ;

          }

}

int split ( int a[ ], int lower, int upper )

{

          int i, p, q, t ;

p = lower + 1 ;

          q = upper ;

          i = a[lower] ;

while ( q >= p )

          {

                   while ( a[p] < i )

                             p++ ;

while ( a[q] > i )

                             q-- ;

if ( q > p )

                   {

                             t = a[p] ;

                             a[p] = a[q] ;

                             a[q] = t ;

                   }

          }

t = a[lower] ;

          a[lower] = a[q] ;

          a[q] = t ;

return q ;

}