1 /*-----------------------------------------------------------------------------+
2 Interval Container Library
3 Author: Joachim Faulhaber
4 Copyright (c) 2007-2009: Joachim Faulhaber
5 Copyright (c) 1999-2006: Cortex Software GmbH, Kantstrasse 57, Berlin
6 +------------------------------------------------------------------------------+
7 Distributed under the Boost Software License, Version 1.0.
8 (See accompanying file LICENCE.txt or copy at
9 http://www.boost.org/LICENSE_1_0.txt)
10 +-----------------------------------------------------------------------------*/
11
12 /** Example partys_height_average.cpp \file partys_height_average.cpp
13 \brief Using <i>aggregate on overlap</i> a history of height averages of
14 party guests is computed.
15
16 In partys_height_average.cpp we compute yet another aggregation:
17 The average height of guests as it changes over time. This is done by
18 defining a class counted_sum that sums up heights and counts the number
19 of guests via an operator +=.
20
21 Based on the operator += we can aggregate counted sums on addition
22 of interval value pairs into an interval_map.
23
24 \include partys_height_average_/partys_height_average.cpp
25 */
26 //[example_partys_height_average
27 // The next line includes <boost/date_time/posix_time/posix_time.hpp>
28 // and a few lines of adapter code.
29 #include <boost/icl/ptime.hpp>
30 #include <iostream>
31 #include <boost/icl/interval_map.hpp>
32 #include <boost/icl/split_interval_map.hpp>
33
34 using namespace std;
35 using namespace boost::posix_time;
36 using namespace boost::icl;
37
38
39 class counted_sum
40 {
41 public:
counted_sum()42 counted_sum():_sum(0),_count(0){}
counted_sum(int sum)43 counted_sum(int sum):_sum(sum),_count(1){}
44
sum() const45 int sum()const {return _sum;}
count() const46 int count()const{return _count;}
average() const47 double average()const{ return _count==0 ? 0.0 : _sum/static_cast<double>(_count); }
48
operator +=(const counted_sum & right)49 counted_sum& operator += (const counted_sum& right)
50 { _sum += right.sum(); _count += right.count(); return *this; }
51
52 private:
53 int _sum;
54 int _count;
55 };
56
operator ==(const counted_sum & left,const counted_sum & right)57 bool operator == (const counted_sum& left, const counted_sum& right)
58 { return left.sum()==right.sum() && left.count()==right.count(); }
59
60
partys_height_average()61 void partys_height_average()
62 {
63 interval_map<ptime, counted_sum> height_sums;
64
65 height_sums +=
66 make_pair(
67 discrete_interval<ptime>::right_open(
68 time_from_string("2008-05-20 19:30"),
69 time_from_string("2008-05-20 23:00")),
70 counted_sum(165)); // Mary is 1,65 m tall.
71
72 height_sums +=
73 make_pair(
74 discrete_interval<ptime>::right_open(
75 time_from_string("2008-05-20 19:30"),
76 time_from_string("2008-05-20 23:00")),
77 counted_sum(180)); // Harry is 1,80 m tall.
78
79 height_sums +=
80 make_pair(
81 discrete_interval<ptime>::right_open(
82 time_from_string("2008-05-20 20:10"),
83 time_from_string("2008-05-21 00:00")),
84 counted_sum(170)); // Diana is 1,70 m tall.
85
86 height_sums +=
87 make_pair(
88 discrete_interval<ptime>::right_open(
89 time_from_string("2008-05-20 20:10"),
90 time_from_string("2008-05-21 00:00")),
91 counted_sum(165)); // Susan is 1,65 m tall.
92
93 height_sums +=
94 make_pair(
95 discrete_interval<ptime>::right_open(
96 time_from_string("2008-05-20 22:15"),
97 time_from_string("2008-05-21 00:30")),
98 counted_sum(200)); // Peters height is 2,00 m
99
100 interval_map<ptime, counted_sum>::iterator height_sum_ = height_sums.begin();
101 cout << "-------------- History of average guest height -------------------\n";
102 while(height_sum_ != height_sums.end())
103 {
104 discrete_interval<ptime> when = height_sum_->first;
105
106 double height_average = (*height_sum_++).second.average();
107 cout << setprecision(3)
108 << "[" << first(when) << " - " << upper(when) << ")"
109 << ": " << height_average <<" cm = " << height_average/30.48 << " ft" << endl;
110 }
111 }
112
113
main()114 int main()
115 {
116 cout << ">>Interval Container Library: Sample partys_height_average.cpp <<\n";
117 cout << "------------------------------------------------------------------\n";
118 partys_height_average();
119 return 0;
120 }
121
122 // Program output:
123 /*-----------------------------------------------------------------------------
124 >>Interval Container Library: Sample partys_height_average.cpp <<
125 ------------------------------------------------------------------
126 -------------- History of average guest height -------------------
127 [2008-May-20 19:30:00 - 2008-May-20 20:10:00): 173 cm = 5.66 ft
128 [2008-May-20 20:10:00 - 2008-May-20 22:15:00): 170 cm = 5.58 ft
129 [2008-May-20 22:15:00 - 2008-May-20 23:00:00): 176 cm = 5.77 ft
130 [2008-May-20 23:00:00 - 2008-May-21 00:00:00): 178 cm = 5.85 ft
131 [2008-May-21 00:00:00 - 2008-May-21 00:30:00): 200 cm = 6.56 ft
132 -----------------------------------------------------------------------------*/
133 //]
134
135