How are you?
I have a qsort() question. Can you do qsort only on a part of an array (not the entire array).
For example if I have:
int myArray[50];
and I want to sort myArray between entries 10 and 20 only (and not touch the array between 0...9 and 21...49), would that be possible.
What would be the syntax of such a sort.
Thank you very much.

yes you can where you will send the lower index as 10 and higher index as 20. Here is a smaple code for q sort.

class QSortAlgorithm extends SortAlgorithm
  /** This is a generic version of C.A.R Hoare's Quick Sort
   * algorithm.  This will handle arrays that are already
   * sorted, and arrays with duplicate keys.
   * If you think of a one dimensional array as going from
   * the lowest index on the left to the highest index on the right
   * then the parameters to this function are lowest index or
   * left and highest index or right.  The first time you call
   * this function it will be with the parameters 0, a.length - 1.
   * @param a       an integer array
   * @param lo0     left boundary of array partition
   * @param hi0     right boundary of array partition
  void QuickSort(int a[], int lo0, int hi0) throws Exception
     int lo = lo0;
     int hi = hi0;
     int mid;

     // pause for redraw
     pause(lo, hi);
     if ( hi0 > lo0)

        /* Arbitrarily establishing partition element as the midpoint of
         * the array.
        mid = a[ ( lo0 + hi0 ) / 2 ];

        // loop through the array until indices cross
        while( lo <= hi )
         /* find the first element that is greater than or equal to
         * the partition element starting from the left Index.
         while( ( lo < hi0 ) && ( a[lo] < mid ) )

         /* find an element that is smaller than or equal to
         * the partition element starting from the right Index.
         while( ( hi > lo0 ) && ( a[hi] > mid ) )

         // if the indexes have not crossed, swap
         if( lo <= hi )
         swap(a, lo, hi);
         // pause


        /* If the right index has not reached the left side of array
         * must now sort the left partition.
        if( lo0 < hi )
         QuickSort( a, lo0, hi );

        /* If the left index has not reached the right side of array
         * must now sort the right partition.
        if( lo < hi0 )
         QuickSort( a, lo, hi0 );


  private void swap(int a[], int i, int j)
     int T;
     T = a[i];
     a[i] = a[j];
     a[j] = T;


  public void sort(int a[]) throws Exception
     QuickSort(a, 0, a.length - 1);


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