I can't get seem to get this quicksort algorithm to work...

[Tom Liu]

Can anyone help me? I've tried and tried and tried, but I can't seem to get this quicksort algorithm to work. I can't seem to find whats wrong with it. The sorting is perfect in most cases except one of the number is out of place. Sometimes, an infinite loop occurs. Here's the code:

 static int partition(int array[], int l, int r){
int i = l; int j = r-1; int v = array[r];

for(;; ) 
{
while(array[i]<v)
{
if(i>=j) break;
i++;
}
while(array[j]>v)
{
if(i>=j) break;
j--;
}

if(j==i) break;

int temp = array[i];
array[i] = array[j];
array[j] = temp;
}

int temp = array[i];
array[i] = v;
array[r] = temp;
return i;
}

static void sort(int array[], int l, int r)
{
if(l>=r) return;
int i = partition(array, l, r);
sort(array, l, i-1);
sort(array, i+1, r);
} 

Please help inspecting it. Thank you very much.
[ May 19, 2005: Message edited by: Tom Liu ]

[Ilja Preuss]

What is the minimal sequence of ints that fails to get sorted correctly?

[Mihai Alexe]

Try entering a sequence of values that cause an infinite loop to occur and then step with any IDE debugger to see what fails. This should reveal the problem.
[ May 23, 2005: Message edited by: Mihai Alexe ]