| /*-----------------------------------------------------------------------------+ |
| 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 |
| -----------------------------------------------------------------------------*/ |
| //] |
| |