空语句的测试

空语句的作用：消耗CPU时间，起到延时的作用

int main(){    long i = 100000000;    clock_t start, finish;    double Total_time;    printf("Time to do %ld empty loops is ", i);    start = clock();    while (i--);//当i足够大时，可以看到明显的耗时    finish = clock();    Total_time = (double)(finish - start) / CLOCKS_PER_SEC;//CLOCKS_PER_SEC=1000    printf("%f seconds/n", Total_time);    return 0;}