(C++) Answer of exercise \#9: No for-loops \#27

January 9, 2018 · View on GitHub

 

 

 

 

 

(C++) Answer of exercise #9: No for-loops #27

 

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

 

 

 

 

 

Question #27: HasId on std::vector<Person*>

 

Replace the for-loop. You will need:

 

#include <vector> #include <boost/numeric/conversion/cast.hpp> struct Person {   Person(const int id) : m_id(id) {}   int GetId() const { return m_id; }   const int m_id; }; bool HasId(const std::vector<const Person *>& v, const int id) {   const int size = boost::numeric_cast<int>(v.size());   for (int i=0; i!=size; ++i)   {     if (v[i]->GetId() == id) return true;   }   return false; }

 

 

 

 

 

 

Boost Answer using Boost.Bind

 

#include <algorithm> #include <vector> #include <boost/bind.hpp> #include <boost/lambda/lambda.hpp> struct Person {   Person(const int id) : m_id(id) {}   int GetId() const { return m_id; }   const int m_id; }; bool HasId(const std::vector<const Person *>& v, const int id) {   return std::find_if(     v.begin(),v.end(),     boost::bind(&Person::GetId, boost::lambda::_1) == id     ) != v.end(); }