纯C++的获取系统时间及C风格获取时间戳;C++计算耗时

1. c++获取时间戳,转成格式化

    #include <iostream>
    #include<chrono>
    #include <string>

    std::string getCurrentSystemTime()
    {
            auto tt = std::chrono::system_clock::to_time_t
            (std::chrono::system_clock::now());
            struct tm* ptm = localtime(&tt);
            char date[60] = { 0 };
            sprintf(date, "%d-%02d-%02d-%02d-%02d-%02d",
                    (int)ptm->tm_year + 1900, (int)ptm->tm_mon + 1, (int)ptm->tm_mday,
                    (int)ptm->tm_hour, (int)ptm->tm_min, (int)ptm->tm_sec);
            return std::string(date);
    }

    int main()
    {
            std::string str_time = getCurrentSystemTime();
            std::cout << "str_time: " << str_time << std::endl;
            std::cin.get();
            return 0;
    }

2. 最简单的单纯获取时间戳,C语言风格

#include <time.h>
time_t time = time(0);
std::cout << "time = " << time << std::endl;//1631371273

char * strTime = ctime(&time);
cout << "strTime = " << strTime << endl;//Thu Jun 22 17:13:07 2017

double betweenSecond = difftime(endTime, startTime);

3. std::chrono计算耗时

auto t1=std::chrono::steady_clock::now();
//run code
auto t2=std::chrono::steady_clock::now();

//秒
double dr_s=std::chrono::duration<double>(t2-t1).count();
//毫秒级
double dr_ms=std::chrono::duration<double,std::milli>(t2-t1).count();
//微妙级
double dr_us=std::chrono::duration<double,std::micro>(t2-t1).count();
//纳秒级
double dr_ns=std::chrono::duration<double,std::nano>(t2-t1).count();