Knuth shuffle - 'Algorithm P' C code

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

int main(int argc, char *argv[])
{
    // Define the size of the array and initialize it.
    #define ARRAY_SIZE 10
    int array[ARRAY_SIZE];

    // For this example the array to be shuffled is filled with the values 0..9.
    int i;
    for (i = 0; i < ARRAY_SIZE; i++)
        array[i] = i;

    // Initialize the random number generator.
    srand((unsigned) time(NULL));

    // Start at the length of the array.
    int index = ARRAY_SIZE;

    // Note the use of "index > 1" rather than "index > 0". If "index > 0" was used
    // then the final pass through the loop would always swap index 0 with itself.
    while (index > 1)
    {
        // Create a random number in the range 0..index-1.
        int randomNum = (int) ((double) rand() / ((double) RAND_MAX + 1) * index);

        // Decrement index by 1, the loop travels down through the array.
        index = index - 1;

        // Swap the array elements at positions index and randomNum.
        int temp = array[index];
        array[index] = array[randomNum];
        array[randomNum] = temp;
    }
    return 0;
}