Generate the Cartesian Product of 2 vectors In-Place?

Question

If I want to get the Cartesian Product of these two vectors:

vector final{\"a\",\"b\",\"c\"};
vector temp{         


        

Answer 1

This works for me:

void testCartesianString(vector& final,
                         vectorconst& temp)
{
   size_t size1 = final.size();
   size_t size2 = temp.size();

   // Step 1.
   // Transform final to : {"a","a","b","b","c","c"}
   final.resize(size1*size2);
   for ( size_t i = size1; i > 0; --i )
   {
      for ( size_t j = (i-1)*size2; j < i*size2; ++j )
      {
         final[j] = final[i-1];
      }
   }

   // Step 2.
   // Now fix the values and
   // change final to : {"a1","a2","b1","b2","c1","c2"}
   for ( size_t i = 0; i < size1; ++i )
   {
      for ( size_t j = 0; j < size2; ++j )
      {
         final[i*size2+j] = final[i*size2+j] + temp[j];
         cout << final[i*size2+j] << " ";
      }
      cout << endl;
   }
}