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- /*-----------------------------------------------------------------------------+
- Interval Container Library
- Author: Joachim Faulhaber
- Copyright (c) 2007-2009: Joachim Faulhaber
- Copyright (c) 1999-2006: Cortex Software GmbH, Kantstrasse 57, Berlin
- +------------------------------------------------------------------------------+
- Distributed under the Boost Software License, Version 1.0.
- (See accompanying file LICENCE.txt or copy at
- http://www.boost.org/LICENSE_1_0.txt)
- +-----------------------------------------------------------------------------*/
- /** Example partys_height_average.cpp \file partys_height_average.cpp
- \brief Using <i>aggregate on overlap</i> a history of height averages of
- party guests is computed.
- In partys_height_average.cpp we compute yet another aggregation:
- The average height of guests as it changes over time. This is done by
- defining a class counted_sum that sums up heights and counts the number
- of guests via an operator +=.
-
- Based on the operator += we can aggregate counted sums on addition
- of interval value pairs into an interval_map.
- \include partys_height_average_/partys_height_average.cpp
- */
- //[example_partys_height_average
- // The next line includes <boost/date_time/posix_time/posix_time.hpp>
- // and a few lines of adapter code.
- #include <boost/icl/ptime.hpp>
- #include <iostream>
- #include <boost/icl/interval_map.hpp>
- #include <boost/icl/split_interval_map.hpp>
- using namespace std;
- using namespace boost::posix_time;
- using namespace boost::icl;
- class counted_sum
- {
- public:
- counted_sum():_sum(0),_count(0){}
- counted_sum(int sum):_sum(sum),_count(1){}
- int sum()const {return _sum;}
- int count()const{return _count;}
- double average()const{ return _count==0 ? 0.0 : _sum/static_cast<double>(_count); }
- counted_sum& operator += (const counted_sum& right)
- { _sum += right.sum(); _count += right.count(); return *this; }
- private:
- int _sum;
- int _count;
- };
- bool operator == (const counted_sum& left, const counted_sum& right)
- { return left.sum()==right.sum() && left.count()==right.count(); }
- void partys_height_average()
- {
- interval_map<ptime, counted_sum> height_sums;
- height_sums +=
- make_pair(
- discrete_interval<ptime>::right_open(
- time_from_string("2008-05-20 19:30"),
- time_from_string("2008-05-20 23:00")),
- counted_sum(165)); // Mary is 1,65 m tall.
- height_sums +=
- make_pair(
- discrete_interval<ptime>::right_open(
- time_from_string("2008-05-20 19:30"),
- time_from_string("2008-05-20 23:00")),
- counted_sum(180)); // Harry is 1,80 m tall.
- height_sums +=
- make_pair(
- discrete_interval<ptime>::right_open(
- time_from_string("2008-05-20 20:10"),
- time_from_string("2008-05-21 00:00")),
- counted_sum(170)); // Diana is 1,70 m tall.
- height_sums +=
- make_pair(
- discrete_interval<ptime>::right_open(
- time_from_string("2008-05-20 20:10"),
- time_from_string("2008-05-21 00:00")),
- counted_sum(165)); // Susan is 1,65 m tall.
- height_sums +=
- make_pair(
- discrete_interval<ptime>::right_open(
- time_from_string("2008-05-20 22:15"),
- time_from_string("2008-05-21 00:30")),
- counted_sum(200)); // Peters height is 2,00 m
- interval_map<ptime, counted_sum>::iterator height_sum_ = height_sums.begin();
- cout << "-------------- History of average guest height -------------------\n";
- while(height_sum_ != height_sums.end())
- {
- discrete_interval<ptime> when = height_sum_->first;
- double height_average = (*height_sum_++).second.average();
- cout << setprecision(3)
- << "[" << first(when) << " - " << upper(when) << ")"
- << ": " << height_average <<" cm = " << height_average/30.48 << " ft" << endl;
- }
- }
- int main()
- {
- cout << ">>Interval Container Library: Sample partys_height_average.cpp <<\n";
- cout << "------------------------------------------------------------------\n";
- partys_height_average();
- return 0;
- }
- // Program output:
- /*-----------------------------------------------------------------------------
- >>Interval Container Library: Sample partys_height_average.cpp <<
- ------------------------------------------------------------------
- -------------- History of average guest height -------------------
- [2008-May-20 19:30:00 - 2008-May-20 20:10:00): 173 cm = 5.66 ft
- [2008-May-20 20:10:00 - 2008-May-20 22:15:00): 170 cm = 5.58 ft
- [2008-May-20 22:15:00 - 2008-May-20 23:00:00): 176 cm = 5.77 ft
- [2008-May-20 23:00:00 - 2008-May-21 00:00:00): 178 cm = 5.85 ft
- [2008-May-21 00:00:00 - 2008-May-21 00:30:00): 200 cm = 6.56 ft
- -----------------------------------------------------------------------------*/
- //]
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