C++每日一练4.获取当前系统时间系统时间戳

Posted 2022-01-07 鱼酱2333

需求：获取当前系统时间、系统时间戳

#include <iostream>
#include <chrono>
#include <cstdio>
using namespace std;

std::time_t getTimeStamp()

    std::chrono::time_point<std::chrono::system_clock, std::chrono::milliseconds> tp = std::chrono::time_point_cast<std::chrono::milliseconds>(std::chrono::system_clock::now());
    auto tmp = std::chrono::duration_cast<std::chrono::milliseconds>(tp.time_since_epoch());
    std::time_t timestamp = tmp.count();

    return timestamp;


std::tm *gettm(long long timestamp)

    auto milli = timestamp + (long long)8 * 60 * 60 * 1000; //此处转化为东八区北京时间，如果是其它时区需要按需求修改
    auto mTime = std::chrono::milliseconds(milli);
    auto tp = std::chrono::time_point<std::chrono::system_clock, std::chrono::milliseconds>(mTime);
    auto tt = std::chrono::system_clock::to_time_t(tp);
    std::tm *now = std::gmtime(&tt);
   return now;



int main()

    char time_str[4][16];
    auto t = getTimeStamp();
    std::cout << "Millisecond timestamp is: " << t << std::endl;
    auto time_ptr = gettm(t);
    sprintf(time_str[0], "%02d", time_ptr->tm_mon + 1); //月份要加1
    sprintf(time_str[1], "%02d", time_ptr->tm_mday);//天
    sprintf(time_str[2], "%02d", time_ptr->tm_hour);//时
    sprintf(time_str[3], "%02d", time_ptr->tm_min);// 分
    for(int i = 0; i < 4; i++)
    
        std::cout << "time_str[" << i << "] is: " << time_str[i] << std::endl;