linux c语言计时器

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

int main() {
    time_t start, end;
    double seconds;

    time(&start);
    // 模拟一些操作
    sleep(2);
    time(&end);

    seconds = difftime(end, start);
    printf("Time elapsed: %.2f seconds
", seconds);

    return 0;
}

#include <stdio.h>
#include <sys/time.h>

int main() {
    struct timeval start, end;
    double elapsed;

    gettimeofday(&start, NULL);
    // 模拟一些操作
    sleep(2);
    gettimeofday(&end, NULL);

    elapsed = (end.tv_sec - start.tv_sec) + (end.tv_usec - start.tv_usec) / 1000000.0;
    printf("Time elapsed: %.6f seconds
", elapsed);

    return 0;
}

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

int main() {
    struct timespec start, end;
    double elapsed;

    clock_gettime(CLOCK_MONOTONIC, &start);
    // 模拟一些操作
    sleep(2);
    clock_gettime(CLOCK_MONOTONIC, &end);

    elapsed = (end.tv_sec - start.tv_sec) + (end.tv_nsec - start.tv_nsec) / 1e9;
    printf("Time elapsed: %.9f seconds
", elapsed);

    return 0;
}