Question

Say I have a

struct SMyStruct  {    int MULT;    int VAL;  };   std::map<std::string, SMyStuct*> _idToMyStructMap; 

Now I want to calculate total of all SMyStuct, where total is defined as MULT1 *VAL1 + MULT2 *VAL2 for each elements in the idToMyStructMap.

Seems like accumulate function is a natural choice. Please suggest. thanks

No Boost please…. just an ‘ld fashion stl

Answer 1

typedef std::map< std::string, SMyStruct* > string_to_struct_t;  int add_to_totals( int total, const string_to_struct_t::value_type& data ) {     return total + data.second->MULT * data.second->VAL;  }  const int total = std::accumulate(                          _idToMyStructMap.begin(),                          _idToMyStructMap.end(),                          0,                           add_to_totals );