Boost--时间和日期--（1）timer库的介绍

#include <boost/timer.hpp>
#include <iostream>

int main(int argc,char * argv[]){
    boost::timer t;
    //获取timer能够表示的最大时间精度
    std::cout<<"max timespan : "<<t.elapsed_max()/3600<<"h"<<std::endl;
    //获取timer能够表示的最小时间精度
    std::cout<<"min timespan : "<<t.elapsed_min()<<"s"<<std::endl;
    std::cout<<"now time elapsed : "<<t.elapsed()<<"s"<<std::endl;
    return 0;
}

//  boost timer.hpp header file  ---------------------------------------------//
//  Copyright Beman Dawes 1994-99.  Distributed under the Boost
//  Software License, Version 1.0. (See accompanying file
//  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//  See http://www.boost.org/libs/timer for documentation.

//  Revision History
//  01 Apr 01  Modified to use new <boost/limits.hpp> header. (JMaddock)
//  12 Jan 01  Change to inline implementation to allow use without library
//             builds. See docs for more rationale. (Beman Dawes) 
//  25 Sep 99  elapsed_max() and elapsed_min() added (John Maddock)
//  16 Jul 99  Second beta
//   6 Jul 99  Initial boost version

#ifndef BOOST_TIMER_HPP
#define BOOST_TIMER_HPP

#include <boost/config.hpp>
#include <ctime>
#include <boost/limits.hpp>

# ifdef BOOST_NO_STDC_NAMESPACE
    namespace std { using ::clock_t; using ::clock; }
# endif

namespace boost {

//  timer  -------------------------------------------------------------------//
//  A timer object measures elapsed time.
//  It is recommended that implementations measure wall clock rather than CPU
//  time since the intended use is performance measurement on systems where
//  total elapsed time is more important than just process or CPU time.

//  Warnings: The maximum measurable elapsed time may well be only 596.5+ hours
//  due to implementation limitations.  The accuracy of timings depends on the
//  accuracy of timing information provided by the underlying platform, and
//  this varies a great deal from platform to platform.

class timer
{
 public:
         timer() { _start_time = std::clock(); } // postcondition: elapsed()==0
//         timer( const timer& src );      // post: elapsed()==src.elapsed()
//        ~timer(){}
//  timer& operator=( const timer& src );  // post: elapsed()==src.elapsed()
  void   restart() { _start_time = std::clock(); } // post: elapsed()==0
  double elapsed() const                  // return elapsed time in seconds
    { return  double(std::clock() - _start_time) / CLOCKS_PER_SEC; }

  double elapsed_max() const   // return estimated maximum value for elapsed()
  // Portability warning: elapsed_max() may return too high a value on systems
  // where std::clock_t overflows or resets at surprising values.
  {
    return (double((std::numeric_limits<std::clock_t>::max)())
       - double(_start_time)) / double(CLOCKS_PER_SEC); 
  }

  double elapsed_min() const            // return minimum value for elapsed()
   { return double(1)/double(CLOCKS_PER_SEC); }

 private:
  std::clock_t _start_time;
}; // timer

} // namespace boost

#endif  // BOOST_TIMER_HPP

{
    boost::progress_timer t; //析构时自动输出时间间隔（从对象创建到析构）
    //do something...
}

#include <iostream>
#include <boost/progress.hpp>

int main(int argc,char * argv[]){
    //声明基数大小为100
    boost::progress_display pd(100);
    for(int i=0;i<100;i++){
        ++pd;
    }
    
    return 0;
}