c++ - Iteration on Quick Sort -

i trying implement quick sort now. but, have problem loop part below

for (int current = 0; current <= high - 1; current++) 

when initialize 'current' statement 0, show nothing on screen when run it. then, try replace 'low' argument in implementation provided , run appropriately.

what want ask is, why doesn't work when initialize loop statement 0, same value assigned 'low' parameter? have tried initialize new variable 0 , use variable loop, give same result when directly assign loop statement 0. answer.

here code:

int partition(int arr[], int low, int high) {     int pivot = arr[high];     int index = (low - 1);     (int current = low; current <= high - 1; current++)     {         if (arr[current] <= pivot)         {             index++;             swap(arr[index], arr[current]);         }     }     swap(arr[index+1], arr[high]);     return (index + 1); }  void quicksort(int arr[], int low, int high) {     if (low < high)     {         int pi = partition(arr, low, high);         quicksort(arr, low, pi - 1);         quicksort(arr, pi + 1, high);     } }   int main() {     int arr[] = { 3, 4, 2, 5, 1 };     int n = sizeof(arr)/sizeof(arr[0]);     quicksort(arr, 0, n-1);     (int = 0; < n; i++)     {         cout << arr[i] << " ";     } } 

the result when set 'current' value 0

low 0 in first call partition; takes different values in other calls. note when quicksort calls second time, low assigned pi + 1.

print out in beginning of partition observe known not-too-large array - should educational exercise in general. mean make first line of partition:

cout << "low = " << low << "\n";