Ans.

An algorithm for the quick sort is as follows:

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 ; }