Why doesn't count return the correct value for a set C++ object? -

i have set object containing struct data elements. however, count seems returning "1" when object isn't contained within set object. seems looking @ first element of struct. doing wrong? here example of code:

i did implement "<" , "==" operators well:

struct drugkey_tp { std::string alert_uuid;                     std::string patient_id;                     std::string claim_id;                     std::string ndc_code;  };  inline bool operator<(const drugkey_tp &lhs,                        const drugkey_tp &rhs) {      return (lhs.alert_uuid < rhs.alert_uuid &&              lhs.ndc_code < rhs.ndc_code &&              lhs.claim_id < rhs.claim_id &&              lhs.ndc_code < rhs.ndc_code);  };  inline bool operator==(const drugkey_tp &lhs, const drugkey_tp &rhs) {      return (lhs.alert_uuid == rhs.alert_uuid &&              lhs.patient_id == rhs.patient_id &&               lhs.claim_id == rhs.claim_id &&              lhs.ndc_code == rhs.ndc_code);  }; 

here check see if objects exist , add them if don't:

drugkey_tp drugkey; static set<drugkey_tp> savedrxdetails;  ... drugkey.alert_uuid = <some value>; drugkey.patient_id = <some value>; drugkey.claim_id = <some value>; drugkey.ndc_code = <some value>;      if (savedrxdetails.count(drugkey) == 0) {        // save detail if detail has not been saved        savedrxdetails.insert(drugkey);           }     else {         return;     } 

i added following 4 values "savedrxdetails":

alert id   = e51ed799-10c5-475f-9474-1a403b85a83c patient_id = 4513004328217 claim_id   = 126872102351 ndc_code   = 55111059430 

then next call code, following struct values checked see if exist within savedrxdetails. when call "savedrxdetails.count(drugkey)" values below, value returned "1":

 alert id   = e51ed799-10c5-475f-9474-1a403b85a83c  patient_id = 4513004328217  claim_id   = 114225128231  ndc_code   = 00006027531 

you can see first element (alert_id) , second element (patient_id) of struct matches, none of rest of does. need implement other operator other "<" , "==" "count" method work correctly?

you didn't implement comparison correctly. you're supposed compare first fields differ:

if (lhs.alert_uuid != rhs.alert_uuid)     return lhs.alert_uuid < rhs.alert_uuid; else if (lhs.ndc_code != rhs.ndc_code)     return lhs.ndc_code < rhs.ndc_code; else if ( /* etc ... */ ) 

this more done using std::tuple's comparison:

#include <tuple>  return     std::tie(lhs.alert_uuid, lhs.ndc_code, lhs.claim_id, lhs.patient_id) <     std::tie(rhs.alert_uuid, rhs.ndc_code, rhs.claim_id, rhs.patient_id);