error C2679: binary '=' : no operator found in a const class method

[henry1999sg]

When I change a class method to 'const', got the following errors. Any guru can help look into it ? Thanks in advance.

error C2679: binary '=' : no operator found which takes a right-hand operand of type 'std::_Tree<_Traits>::const_iterator' (or there is no acceptable conversion)
with
[
_Traits=std::_Tmap_traits<std::string,std::string,std::less<std::string>,std::allocator<std::pair<const std::string,std::string>>,false>
]

--------------------

1 2 3 4 5 6 7 8 9 10

h file class ReadConfigFile { public: ReadConfigFile(const char *pszFileName); int GetParameter(const char *, char *) const; }

cpp file int ReadConfigFile::GetParameter(const char *pszParameterKey, char *pszRetParameter) const { std::map<std::string, std::string>::iterator itr; for( itr = m_parameters.begin(); itr != m_parameters.end(); itr++) ------------------- the client ReadConfigFile cfgFile(g_confFile); char tmp[250]; if(cfgFile.GetParameter("start_date",tmp)) strcpy(startDate,tmp);

[henry1999sg]

sorry solved.
I just change the iterator to const_iterator