Check the execution time of the program in C language

int main(int argc, char const *argv[]) {
    clock_t begin = clock();

    int j = 0;
    for(int i=0;i<500000;i++)
        j++;

    clock_t end = clock();
    double time_spent = (double)(end - begin) / CLOCKS_PER_SEC;
    printf("%lf", time_spent);
    return 0;
}