Quick Sort in C

Here’s the example of Quick sort in c.

#include < stdio.h >
#include < conio.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 ) ;

clrscr( ) ;

printf ( “Quick sort.\n” ) ;

printf ( “\nArray before sorting:\n”) ;

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

printf ( "%d\t", arr[i] ) ;

quicksort ( arr, 0, 9 ) ;

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

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

printf ( "%d\t", arr[i] ) ;

getch( ) ;
}

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 ;
}