Searching through a const std::map - c++

Question

I am working on one of my classes and I have come upon a stumbling block. I'll give you a sample of my source only the names of classes, methods and variable names are different, but the implementation is the same. You will see my problem/s, question/s & concern/s within the code block to the appropriate function.
MyClass.h
#ifndef MY_CLASS_H
#define MY_CLASS_H
const std::string strOne = std::string( "one" );
const std::string strTwo = std::string( "two" );
const std::string strThree = std::string( "three" );
const std::string strUnknown = std::string( "unknown" );
enum Count {
ONE,
TWO,
THREE,
UNKNOWN
};
class MyClass {
private:
const std::map<Count, const std::string> m_mCount = createCountMap();
unsigned short m_uCount;
std::vector<std::string> m_vItems;
std::multimap<const std::string, const std::string> m_mmAssociatedItems;
public:
MyClass();
MyClass( const std::string strItem1, const std::string strItem2 );
static MyClass* get();
void addItem( Count type, const std::string& strItem2 );
void addItem( const std::string& strItem1, const std::string& strItem2 );
private:
static const std::map<Count, const std::string> createCountMap();
};
#endif // MY_CLASS_H
MyClass.cpp
#include "stdafx.h"
#include "MyClass.h"
static MyClass* s_pMyClass = nullptr;
const std::map<Count, const std::string> MyClass:createCountMap() {
std::map<Count, const std::string> m;
m.insert( std::make_pair( Count::ONE, strOne ) );
m.insert( std::make_pair( Count::TWO, strTwo ) );
m.insert( std::make_pair( Count::Three, strThree ) );
m.insert( std::make_pair( Count::UNKNOWN, strUnknown ) );
return m;
} // createCountMap
MyClass* MyClass::get() {
if ( !s_pMyClass ) {
return nullptr;
}
return s_pMyClass;
} // get
MyClass::MyClass() : m_uCount( 0 ) {
m_vItems.clear();
m_mmAssociatedItems.clear();
} // MyClass
MyClass::MyClass( const std::string& strItem1, const std::string& strItem2 ) :
m_uCount( 0 ) {
addItem( strItem1, strItem2 );
} // MyClass
void MyClass::addItem( Count type, const std::string& strItem2 ) {
const std::map<Count, const std::string>::const_iterator it = m_mCount.find( type );
if ( it == m_mCount.end() ) {
// Did not find a valid item key!
// Throw Exception Here!
}
m_vItems.push_back( strItem2 );
m_mmAssociatedItems.insert( std::make_pair( it->second, m_vItems.at( m_uCount ) ) );
++m_uCount;
}
void MyClass::addItem( const std::string& strItem1, const std::string& strItem2 ) {
// I need to do a similar thing as above instead of looking through my
// const std::map at the key values for a match, with this overloaded
// function call I need to use strItem1 as the search item to see if it
// is within the contents of this map which would be the map's ->second
// value. If not throw a similar error as above otherwise once it is
// found populate my vector and multimap same as above and increment
// my count variable.
// This would logically be my next step
const std::map<Count, const std::string>::const_iterator it = m_mCount.begin();
// It Is Within This For Loop That It Fails To Compile! It
// Fails At The it++ Part! Is There A Way Around This? Or
// Am I Missing Something Simple?
for ( ; it != m_mCount.end(); it++ ) {
// If strItem1 == it->second && it != m_mCount.end()
// found it, add items, if not throw error
}
m_vItems.push_back( strItem2 );
m_mmAssociatedItems.insert( std::make_pair( strItem1, strItem2 ) );
++m_uCount;
}
In my source, it is this second function which is more important then the first! Any Help or suggestions is very much appreciated.

Answer 1

const std::map<Count, const std::string>::const_iterator it = m_mCount.begin();
The first const should be removed. Otherwise it cannot be moved forward, and you cannot iterate through m_mCount.