问使用rand()和rand_r()：这个简单的示例正确吗？

EN

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

int main() {
        /* Initialize and extract an integer via rand() */
        srand(time(NULL));
        int N = rand() % 100;

        /* Storage array */ 
        int *extracted = malloc(sizeof(int) * N);

        /* Initialize N seeds for rand_r, which is completely
         * independent on rand and srand().
         * (QUESTION 1: is it right?)
         * Setting the first as time(NULL), and the others
         * via successive increasing is a good idea (? QUESTION 2)*/
        unsigned int *my_seeds = malloc(sizeof(unsigned int) * N);
        my_seeds[0] = time(NULL);
        for (int i = 1; i < N; ++i) {
                my_seeds[i] = my_seeds[i - 1] + 1;
        }

        /* The seeds for rand_r are ready:
         * extract N random numbers in parallel */
        #pragma omp parallel for
        for (int i = 0; i < N; ++i) {
                extracted[i] = rand_r(my_seeds + i) % 10;
        }

        /* Compute the average: must be done sequentially, QUESTION 3,
         * because of time-sincronization in reading/writing avg */
        double avg = 0;
        for (int i = 0; i < N; ++i) {
                avg += extracted[i];
        }
        avg /= N;
        printf("%d samples, %.2f in average.\n", N, avg);
        return 0;
}