(C++) Answer of exercise \#9: No for-loops \#30

This is the answer of Exercise #9: No for-loops.

 

 

 

 

 

Question #30: Get maximum value from std::map<const Person *,int>

 

Replace the for-loop. You will need:

• boost::bind

 

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#include <cassert> #include <limits> #include <map> #include <boost/foreach.hpp> struct Person { }; const Person * GetPersonWithMaxIdStl(const std::map<const Person *,int>& v) {   assert(!v.empty());   int max_id =  std::numeric_limits<int>::min();   const Person * ptr = 0;   typedef std::pair<const Person *,int> Pair;   BOOST_FOREACH(const Pair& p,v)   {     if (p.second > max_id)     {       max_id = p.second;       ptr = p.first;     }   }   assert(ptr);   return ptr; }

 

 

 

 

 

Answer using Boost.Bind

 

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#include <algorithm> #include <cassert> #include <map> #include <boost/lambda/bind.hpp> #include <boost/lambda/lambda.hpp> struct Person {}; const Person * GetPersonWithMaxId(const std::map<const Person *,int>& v) {   assert(!v.empty());   return std::max_element(     v.begin(),v.end(),     boost::lambda::bind(&std::pair<const Person *,int>::second, boost::lambda::_2)      > boost::lambda::bind(&std::pair<const Person *,int>::second, boost::lambda::_1)    )->first; }