(C++) Answer of exercise #9: No for-loops #2

 

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

 

 

 

 

 

Question #2: Multiply

 

Replace the for-loop. You will need

• std::bind2nd (or boost::bind)
• std::multiplies
• std::transform

 

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#include <vector>   void Multiply(std::vector<int>& v, const int x) {   const int sz = v.size();   for (int i=0; i!=sz; ++i)   {     v[i]*=x;   } }

 

 

 

 

 

Answer using STL only

 

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#include <vector> #include <algorithm> #include <numeric>   void Multiply(std::vector<int>& v, const int x) {   std::transform(v.begin(),v.end(),v.begin(),     std::bind2nd(std::multiplies<int>(),x)); }

 

 

 

 

 

Answer using Boost

 

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#include <vector> #include <algorithm> #include <numeric> #include <boost/bind.hpp>   void Multiply(std::vector<int>& v, const int x) {   std::transform(v.begin(),v.end(),v.begin(),     boost::bind(std::multiplies<int>(),_1,x)); }