#include <stdio.h>
#include <stdlib.h>

    
void print(int a[]) 
{
  for (int i = 0; i < 10; i++) {
    printf("%2d ", a[i]);
  }
  printf("\n");
}

int partition(int a[], int p, int r) 
{
  printf("Before: "); print(a); 
	
  int x = a[r];
  int j = p - 1;
  for (int i = p; i < r; i++) {

    if (x <= a[i]) {
      j = j + 1;
      int temp = a[j];
      a[j] = a[i];
      a[i] = temp;
    }
  }
  a[r] = a[j + 1];
  a[j + 1] = x;

  printf("After:  "); print(a); 
  printf("Pivot == %d\n", a[j+1]);
  
  return (j + 1);
}

void quickSort(int a[], int p, int r) {
  if (p < r) {
    int q = partition(a, p, r);
    quickSort(a, p, q - 1); // sort the left part recursively
    quickSort(a, q + 1, r); // sort the right part
  }
}

int main() 
{

  int a[] = { 1, 9, 0, 5, 6, 7, 8, 2, 4, 3};
  quickSort(a, 0, 9);
  print(a);
  system("pause");
}