Quick Sort

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

void printData(double *Data, int L, int R) {
  for (int i = L; i <= R ; i++) {
    printf("%g ", Data[i]);
  }
  printf("\n");
}

void swap(double *x, double *y) {
  double swap = *x;
  *x = *y;
  *y = swap;
}

void quickSortBase(double *Data, int L, int R) {
  int pivot_index = (L + R) / 2;
  double pivot = Data[pivot_index];
  printf("sorting [%d] ... [%d], pivot=[%d]:%g\n", L, R, pivot_index, pivot);
  int i = L;
  int j = R;
  while (1) {
    while (Data[i] < pivot) i++;
    while (pivot < Data[j]) j--;
    if (i >= j) break;
    printf("swapped [%d]:%g <=> [%d]:%g\n", i, Data[i], j, Data[j]);
    swap(&Data[i], &Data[j]);
    i++;
    j--;
  }
  quickSortBase(Data, L, i - 1);
  quickSortBase(Data, j + 1, R);
}

void quickSort(double *Data, int N) {
  if (N >= 2) {
    quickSortBase(Data, 0, N);
  }
}

int main(void) {
  double Data[] = { 1., 3., 4., 3., 5., 5., 2., 4. };
  int N = sizeof(Data) / sizeof(Data[0]);
  quickSort(Data, N);
}