Re: maps turn into multimaps

peter koch <>
Tue, 26 Aug 2008 14:01:08 -0700 (PDT)
On 26 Aug., 22:26, brad <> wrote:

peter koch wrote:

It is unique key, of course. You most likely have a bug in the
comparison function. Show some code if you want more help.


It's a test for credit card pre-validation. I added 13 digit visa cards
to the test in addition to the more common 16 digit visa. The prefix for
all visas is "4" (which I use as the key). See below. As I said, it
works, I was just trying to better understand *why* it works :)

struct card_info
   std::string card_name;
   int card_length;

  typedef std::map<std::string, card_info> cMap;
  cMap card_map;

   // VISA info
   card_info v;
   v.card_name = "Visa";
   v.card_length = 16;
   card_map.insert(std::pair<std::string, card_info>("4", v));

   // VISA13 info
   card_info v13;
   v13.card_name = "Visa";
   v13.card_length = 13;
   card_map.insert(std::pair<std::string, card_info>("4", v13));

You do not validate that the insert succeeds - this is most likey your


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