linux计算程序运行时间

time ./your_program

real    0m1.234s
user    0m0.567s
sys     0m0.123s

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

int main() {
    struct rusage start, end;
    getrusage(RUSAGE_SELF, &start);

    // 这里放置你要测量的代码
    for (volatile int i = 0; i < 100000000; i++);

    getrusage(RUSAGE_SELF, &end);

    long seconds = end.ru_utime.tv_sec - start.ru_utime.tv_sec;
    long micros = end.ru_utime.tv_usec - start.ru_utime.tv_usec;
    double elapsed = seconds + micros*1e-6;

    printf("CPU time used: %.6f seconds
", elapsed);
    return 0;
}

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

int main() {
    struct timespec start, end;
    clock_gettime(CLOCK_MONOTONIC, &start);

    // 这里放置你要测量的代码
    for (volatile int i = 0; i < 100000000; i++);

    clock_gettime(CLOCK_MONOTONIC, &end);

    double elapsed = (end.tv_sec - start.tv_sec) + (end.tv_nsec - start.tv_nsec) / 1e9;
    printf("Elapsed time: %.6f seconds
", elapsed);
    return 0;
}