/*
 * Example: Read command-line arguments and write them into a map
 * with string keys and "set of int" values
 * 
 * To test, for example, execute "./map-and-set-example 3 1 4 1 5 9 2 6 5 3 5 9"
 */
#include <iostream>
#include <map>
#include <set>
#include <string>

int main(int argc, char** argv)
{
   std::map<std::string, std::set<int>> command_line_args;
   for(int i = 0; i < argc; i++)
   {
      if(command_line_args.count(argv[i]) == 0) /* new key, not in the map so far */
      {
         command_line_args[argv[i]] = std::set<int>();  // create new set from default constructor
      }
      command_line_args[argv[i]].insert(i);
   }
   
   /*
    * note that maps (and sets) are sorted data structures,
    * therefore traversal will automatically be sorted by key
    * 
    * let us only show the words that occurred multiple times
    */
   for(auto i = command_line_args.begin(); i != command_line_args.end(); i++)
   {
      if(i->second.size() == 1) continue;  // don't show words that occur only once
      
      /* output text value of command line argument */
      std::cout << "Key: " << i->first << "\t\tValue (list of occurrences):";
      
      /* now iterate over all the positions where it was found */
      for(auto j = i->second.begin(); j != i->second.end(); j++)
         std::cout << "\t" << *j;
      
      std::cout << "\n";
   }
}