set::find with custom equality operator==

dragoncoder <>
Tue, 2 Feb 2010 17:12:30 CST
Hi all, I have the following code.

// db_operators.h


#include <cstring>

struct ecodb2{
   unsigned long long id;
   char code[21];

inline bool operator==(const ecodb2& lhs,
                        const ecodb2& rhs)
     std::cout << "Some text" << std::endl;
     return (( == || !std::strcmp(lhs.code, rhs.code));

struct Compare
     bool operator()(const ecodb2& lhs,
                     const ecodb2& rhs) const
         bool retval = false;
         if( <
             retval = true;
         else if( ==
             retval = std::strcmp(lhs.code, rhs.code);
         return retval;


// main.cpp

#include <iostream>
#include <cstring>
#include <set>

#include <db_operators.h>

int main()
     std::set<ecodb2, Compare> industry_codes;

     ecodb2 val; = 1;

     std::strncpy(val.code, "GOV", sizeof(val.code));

     std::strncpy(val.code, "ABC", sizeof(val.code));

     std::set<ecodb2>::iterator it = industry_codes.find(val);
     if(it != industry_codes.end())
         std::cout << "Found in set" << std::endl;
         std::cout << "Not found in set" << std::endl;

While running this code, I expect to see Found in set (as either id or
code match meaning a perfect match) and also "Some text" being
printed, becasue set::find should call my custom operator==() function
to find a match but the output I get is "Not found in set" and also
"Some text" is not getting printed.

Please help.

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