Linux c++获得代码运行时间

微秒

#include <sys/time.h>    
#include <unistd.h>   
#include <stdio.h>
int main(void){
    struct timeval timeStart, timeEnd, timeSystemStart; 
    double runTime=0, systemRunTime; 
    gettimeofday(&timeSystemStart, NULL );
    while(1){
        gettimeofday(&timeStart, NULL );
        usleep(300000);
        gettimeofday( &timeEnd, NULL ); 
        runTime = (timeEnd.tv_sec - timeStart.tv_sec ) + (double)(timeEnd.tv_usec -timeStart.tv_usec)/1000000;  
        systemRunTime = (timeEnd.tv_sec - timeSystemStart.tv_sec ) + (double)(timeEnd.tv_usec -timeSystemStart.tv_usec)/1000000;    
        printf("runTime is %lf\n", runTime);    
        printf("systemRunTime is %lf\n", systemRunTime);
    }
    return 0;
}

纳秒

clock_gettime(CLOCK_REALTIME, &tim);
          std::cout<<tim.tv_nsec <<std::endl;

c++获得当前是间（精确到秒）

#include<iostream>  
#include<time.h>  
using namespace std;  
  
void main()  
{  
 
//获取系统时间  
time_t now_time=time(NULL);  
//获取本地时间  
tm*  t_tm = localtime(&now_time);  
//转换为年月日星期时分秒结果，如图：  
printf("local time is    : %s\n", asctime(t_tm));  
//将时间转换为秒  
time_t mk_time = mktime(t_tm);  
  
//也可以自己定义一个时间  
//定义截止时间  
struct tm deadline_tm;  
deadline_tm.tm_sec=0;//[0~59]  
deadline_tm.tm_min=10;//[0~59]  
deadline_tm.tm_hour=13;//[0~23]  
deadline_tm.tm_isdst=0;//default  
deadline_tm.tm_mday=31;//[1~31]  
deadline_tm.tm_mon=2;//[0~11]  
}