C ++ typedef，map，迭代器

Question

Can anybody help me with an iterator problem? I'm having something like this:

class SomeClass{

public:
    //Constructor assigns to m_RefPtr a new t_Records
    //Destructor deletes m_RefPtr or decreases m_RefCnt
    //Copy Constructor assigns m_RefPtr to new obj, increases m_RefCnt
    bool Search(const string &);

private:
    //Some private variables

    struct t_Records{ //For reference counting

        int m_RefCnt; //Reference counter

        typedef vector<int> m_Vec;
        typedef map<string, m_Vec> m_Map;
        m_Map m_RecMap;

        t_Records(void){
            m_RefCnt = 1;
        }

    };

    t_Records * m_RefPtr;

};

//Searchs through the map of m_RefPtr, returns true if found
bool SomeClass::Search(const string & keyword){

    //How to create and use an iterator of m_Map???

    return true;

}

As how I mentioned, I'm having troubles with creating (defining) map iterator outside of the struct. The map is initalized and contains some records. Thanks for your reply.

Answer 1

Like this:

// assuming m_RefPtr is properly initialized:
t_Records::m_Map::iterator it = m_RefPtr->m_RecMap.begin();
++it; // etc.

By the way, m_Map is a bad name for a type. By common convention, names prefixed with m_ are used for data members.

Answer 2

You can iterate like this

for (m_Map::iterator it = m_RecMap.begin(); it != m_RecMap.end(); ++it)
{
    // do stuff with *it
}

Or even easier

for (auto it = m_RecMap.begin(); it != m_RecMap.end(); ++it)
{
    // do stuff with *it
}