/* file: functions.c
   Usage: Used together with qsort.c
*/

void qsort(v, left, right)
int v[], left, right;
{
    int i, last;
    void swap();
    
    if (left >= right) 
      /*do nothing if the subarray contains less than 2 elements*/
      return;
    swap(&v[left], &v[(left + right)/2]); /*move the partition element to v[0]*/
    last = left;
    for (i=left+1; i<=right; i++) /*partition the array*/
	if (v[i] < v[left])
	    swap(&v[++last], &v[i]);
    swap(&v[left], &v[last]); /*restore the partition element*/
    qsort(v, left, last-1);
    qsort(v, last+1, right);
}

void swap(i, j)
int *i, *j;
{
    int temp;
    temp=*i; 
    *i=*j; 
    *j=temp;
}