HoarePartitioning.c

Algo: HoarePartition(A,l,r) 

// rightmost element is the pivot element
x = A[r]; 

i = l-1; 
j = r+1;

while true do
  // we search for a too small element in the right part 
  repeat j = j-1 until 
    A[j]≤x; 

  // we search for a too large element in the left part
  repeat i = i+1 until 
    A[i]≥x;  

  // if i and j haven't crossed we exchange
  if i<j then 
    exchange A[i] and A[j] 

  // else: we return the partitioning point
  else 
    return i;