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


#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


#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;

}

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

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

Answer using Boost.Bind