/* Code for exercise 6.12. |  | "C++ Solutions--Companion to The C++ Programming Language, Third Edition" | by David Vandevoorde; Addison-Wesley 1998; ISBN 0-201-30965-3. | | Permission to use, copy, modify, distribute and sell this software | and its documentation for any purpose is hereby granted without fee. | The author makes no representations about the suitability of this | software for any purpose.  It is provided "as is" without express or | implied warranty. `----------------------------------------------------------------------*/#include <iostream>#include <map>#include <numeric>#include <set>#include <string>using std::string;typedef std::multiset<double> SubData;typedef std::map<string, SubData> Data;void collect_data(Data &stats) {   string name;   while (std::cin >> name) {      double datum;      std::cin >> datum;      stats[name].insert(datum);   }}void print_setstats(SubData const &stats) {   std::size_t count = 0;   double sum = 0.0, median;   for (SubData::const_iterator p = stats.begin();        p!=stats.end(); ++p, ++count) {      if (count==(stats.size()-1)/2) {         median = *p;         if (stats.size()%2==0) {            SubData::const_iterator q = p;            median = (median+(*++q))/2.0;         }      }      sum += *p;   }   std::cout << "sum = " << sum             << ", mean = " << sum/double(count)             << ", median = " << median << std::endl;}// merge_stats: move items from the per-name sets to // a global set, so that we can eventually compute the// overall statistics.void merge_stats(SubData &dest, SubData &src) {   // Associative containers can take "insertion hints":   SubData::iterator hint = dest.begin();   for (SubData::iterator p = src.begin(); p!=src.end(); ++p) {      hint = dest.insert(hint, *p);      src.erase(p);   }}void print_stats(Data &stats) {   SubData global_set;   for (Data::iterator p = stats.begin();        p!=stats.end(); ++p) {      cout << (*p).first << ": ";      print_setstats((*p).second);      merge_stats(global_set, (*p).second);   }   cout << "Global stats: ";   print_setstats(global_set);}int main() {   Data stats;   collect_data(stats);   print_stats(stats);   return 0;}