boost 获取时间并格式化

利用boost来获取当前时间又方便快捷，还不用考虑跨平台的问题。

1. 输出YYYYMMDD

#include <boost/date_time/gregorian/gregorian.hpp>
#define BOOST_DATE_TIME_SOURCE

std::string strTime = boost::gregorian::to_iso_string(\
boost::gregorian::day_clock::local_day());

std::cout << strTime.c_str() << std::endl;

2. 输出YYYYMMDD-HH:MM:SS

#include <boost/date_time/posix_time/posix_time.hpp>
#define BOOST_DATE_TIME_SOURCE

std::string strTime = boost::posix_time::to_iso_string(\
boost::posix_time::second_clock::local_time());

// 这时候strTime里存放时间的格式是YYYYMMDDTHHMMSS，日期和时间用大写字母T隔开了

int pos = strTime.find('T');
strTime.replace(pos,1,std::string("-"));
strTime.replace(pos + 3,0,std::string(":"));
strTime.replace(pos + 6,0,std::string(":"));

std::cout << strTime.c_str() << std::endl;

http://blog.csdn.net/morebread/article/details/6742957