rand shuffle

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define NMAX 10
int arr[NMAX];

void swapInts(int *a, int *b) {
  int aux = *a;
  *a = *b;
  *b = aux;
}

int randInRange(int low, int high) {
  return rand() % (high - low + 1) + low;
}

void randShuffle(int arr[], int low, int high) {
  for (int i = low; i <= high; i++) {
    int j = randInRange(low, high);
    swapInts(arr + i, arr + j);
  }
}

void printArray(int arr[], int n) {
  for (int i = 0; i < n; i++) {
    printf("%d ", arr[i]);
  }
  puts("");//*/
}

int main(void) {
  srand(time(NULL));
  for (int i = 0; i < NMAX; i++) {
    arr[i] = i + 1;
  }
  printArray(arr, NMAX);
  randShuffle(arr, 4, 8);
  printArray(arr, NMAX);
  return 0;
}