CppExerciseNoForLoopsAnswer6.md

 

 

 

 

 

(C++) Answer of exercise #9: No for-loops #6

 

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

 

Question #6: Widget::DoIt on Widget*

 

Replace the for-loop. You will need:

• std::for_each
• std::mem_fun (or boost::mem_fn)

 

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#include <vector> struct Widget {   void DoIt() const { /* do it */ } }; void DoIt(const std::vector<Widget*>& v) {   const int sz = static_cast<int>(v.size());   for (int i=0; i!=sz; ++i)   {     v[i]->DoIt();   } }

 

 

 

 

 

Answer STL-only

 

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#include <algorithm> #include <numeric> #include <vector> struct Widget {   void DoIt() const { /* do it */ } }; void DoIt(const std::vector<Widget*>& v) {   std::for_each(v.begin(),v.end(),std::mem_fun(&Widget::DoIt)); }

 

 

 

 

 

Answer using Boost

 

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#include <algorithm> #include <boost/mem_fn.hpp> #include <vector> struct Widget {   void DoIt() const { /* do it */ } }; void DoIt(const std::vector<Widget*>& v) {   std::for_each(v.begin(),v.end(),boost::mem_fn(&Widget::DoIt)); }