在c++中是否有跨平台的方法来获取当前的日期和时间?


当前回答

我发现这个链接对我的实现非常有用: c++日期和时间

下面是我在实现中使用的代码,以获得清晰的“YYYYMMDD HHMMSS”输出格式。参数in用于在UTC和本地时间之间切换。您可以轻松地修改我的代码以满足您的需要。

#include <iostream>
#include <ctime>

using namespace std;

/**
 * This function gets the current date time
 * @param useLocalTime true if want to use local time, default to false (UTC)
 * @return current datetime in the format of "YYYYMMDD HHMMSS"
 */

string getCurrentDateTime(bool useLocalTime) {
    stringstream currentDateTime;
    // current date/time based on current system
    time_t ttNow = time(0);
    tm * ptmNow;

    if (useLocalTime)
        ptmNow = localtime(&ttNow);
    else
        ptmNow = gmtime(&ttNow);

    currentDateTime << 1900 + ptmNow->tm_year;

    //month
    if (ptmNow->tm_mon < 9)
        //Fill in the leading 0 if less than 10
        currentDateTime << "0" << 1 + ptmNow->tm_mon;
    else
        currentDateTime << (1 + ptmNow->tm_mon);

    //day
    if (ptmNow->tm_mday < 10)
        currentDateTime << "0" << ptmNow->tm_mday << " ";
    else
        currentDateTime <<  ptmNow->tm_mday << " ";

    //hour
    if (ptmNow->tm_hour < 10)
        currentDateTime << "0" << ptmNow->tm_hour;
    else
        currentDateTime << ptmNow->tm_hour;

    //min
    if (ptmNow->tm_min < 10)
        currentDateTime << "0" << ptmNow->tm_min;
    else
        currentDateTime << ptmNow->tm_min;

    //sec
    if (ptmNow->tm_sec < 10)
        currentDateTime << "0" << ptmNow->tm_sec;
    else
        currentDateTime << ptmNow->tm_sec;


    return currentDateTime.str();
}

输出(UTC, EST):

20161123 000454
20161122 190454

其他回答

这适用于g++,我不确定这是否对你有帮助。 项目输出:

The current time is 11:43:41 am
The current date is 6-18-2015 June Wednesday 
Day of month is 17 and the Month of year is 6,
also the day of year is 167 & our Weekday is 3.
The current year is 2015.

代码:

#include <ctime>
#include <iostream>
#include <string>
#include <stdio.h>
#include <time.h>

using namespace std;

const std::string currentTime() {
time_t now = time(0);
struct tm tstruct;
char buf[80];
tstruct = *localtime(&now);
strftime(buf, sizeof(buf), "%H:%M:%S %P", &tstruct);
return buf;
}

const std::string currentDate() {
time_t now = time(0);
struct tm tstruct;
char buf[80];
tstruct = *localtime(&now);
strftime(buf, sizeof(buf), "%B %A ", &tstruct);
return buf;
}

int main() {
    cout << "\033[2J\033[1;1H"; 
std:cout << "The current time is " << currentTime() << std::endl;
    time_t t = time(0);   // get time now
    struct tm * now = localtime( & t );
    cout << "The current date is " << now->tm_mon + 1 << '-' 
         << (now->tm_mday  + 1) << '-'
         <<  (now->tm_year + 1900) 
         << " " << currentDate() << endl; 

 cout << "Day of month is " << (now->tm_mday) 
      << " and the Month of year is " << (now->tm_mon)+1 << "," << endl;
    cout << "also the day of year is " << (now->tm_yday) 
         << " & our Weekday is " << (now->tm_wday) << "." << endl;
    cout << "The current year is " << (now->tm_year)+1900 << "." 
         << endl;
 return 0;  
}

ctime std::

为什么到目前为止只有评论提到了ctime ?

#include <ctime>
#include <iostream>
 
int main()
{
    std::time_t result = std::time(nullptr);
    std::cout << std::ctime(&result);
}

输出

周二 12月 27 5:21:29 PM 2011

下面是不弃用的现代c++解决方案,用于将时间戳作为std::string用于例如文件名:

std::string get_file_timestamp()
{
    const auto now = std::chrono::system_clock::now();
    const auto in_time_t = std::chrono::system_clock::to_time_t(now);

    std::stringstream output_stream;

    struct tm time_info;
    const auto errno_value = localtime_s(&time_info, &in_time_t);
    if(errno_value != 0)
    {
        throw std::runtime_error("localtime_s() failed: " + std::to_string(errno_value));
    }

    output_stream << std::put_time(&time_info, "%Y-%m-%d.%H_%M_%S");
    return output_stream.str();
}

我发现这个链接对我的实现非常有用: c++日期和时间

下面是我在实现中使用的代码,以获得清晰的“YYYYMMDD HHMMSS”输出格式。参数in用于在UTC和本地时间之间切换。您可以轻松地修改我的代码以满足您的需要。

#include <iostream>
#include <ctime>

using namespace std;

/**
 * This function gets the current date time
 * @param useLocalTime true if want to use local time, default to false (UTC)
 * @return current datetime in the format of "YYYYMMDD HHMMSS"
 */

string getCurrentDateTime(bool useLocalTime) {
    stringstream currentDateTime;
    // current date/time based on current system
    time_t ttNow = time(0);
    tm * ptmNow;

    if (useLocalTime)
        ptmNow = localtime(&ttNow);
    else
        ptmNow = gmtime(&ttNow);

    currentDateTime << 1900 + ptmNow->tm_year;

    //month
    if (ptmNow->tm_mon < 9)
        //Fill in the leading 0 if less than 10
        currentDateTime << "0" << 1 + ptmNow->tm_mon;
    else
        currentDateTime << (1 + ptmNow->tm_mon);

    //day
    if (ptmNow->tm_mday < 10)
        currentDateTime << "0" << ptmNow->tm_mday << " ";
    else
        currentDateTime <<  ptmNow->tm_mday << " ";

    //hour
    if (ptmNow->tm_hour < 10)
        currentDateTime << "0" << ptmNow->tm_hour;
    else
        currentDateTime << ptmNow->tm_hour;

    //min
    if (ptmNow->tm_min < 10)
        currentDateTime << "0" << ptmNow->tm_min;
    else
        currentDateTime << ptmNow->tm_min;

    //sec
    if (ptmNow->tm_sec < 10)
        currentDateTime << "0" << ptmNow->tm_sec;
    else
        currentDateTime << ptmNow->tm_sec;


    return currentDateTime.str();
}

输出(UTC, EST):

20161123 000454
20161122 190454

c++与C共享它的日期/时间函数。tm结构可能是c++程序员最容易使用的结构——下面打印今天的日期:

#include <ctime>
#include <iostream>

int main() {
    std::time_t t = std::time(0);   // get time now
    std::tm* now = std::localtime(&t);
    std::cout << (now->tm_year + 1900) << '-' 
         << (now->tm_mon + 1) << '-'
         <<  now->tm_mday
         << "\n";
}