(1) 写代码

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

int main(int argc, char *argv[]) {
    double sec;
    struct timeval tv;
    gettimeofday(&tv, NULL);
    sec = tv.tv_sec;
    sec += tv.tv_usec/1000000.0;
    printf ("hello word!\nsec = %e\n", sec);
    exit(0);
}