Performance check with test (C++)

#include <cstdio>
#include <cstdlib>
#include <ctime>
#include <algorithm>

int Rand() {
    return (rand() << 16) + rand();
}

const int SIZE = 10000000;
int num[SIZE];

int main() {
    freopen("d:\\input.txt", "w", stdout);
    int res_time = 0;
    srand(time(0));
    const int TIMES = 1;
    for (int i = 0; i < TIMES; i++) {
        for (int j = 0; j < SIZE; j++) {
            int cur_num = Rand();
            num[j] = cur_num;
            printf("%d\n", cur_num);
        }
        clock_t s_time = clock();
        std::sort(num, num + SIZE);
        clock_t t_time = clock();
        res_time += t_time - s_time;
    }
    freopen("d:\\time.txt", "w", stdout);
    printf("C++: %.2f\n", (double)res_time / TIMES / CLOCKS_PER_SEC);
}