Re: hash_map : what is wrong?

"K?r?at" <xx@yy.com> ha scritto nel messaggio
news:%23JKVVw3vIHA.2064@TK2MSFTNGP05.phx.gbl...


It seems that you did follow-up neither Brian nor me.

However, I still believe that if you use std::string instead of raw char*
pointers, you will have no access violation.

You may consider the following simple example code, which uses std::string
instead of char* (I renamed your popItem() method as Extract()):

<code>

#include <hash_map>
#include <string>

class IntToString
{
public:

    void Insert( int key, const std::string & value )
    {
        typedef std::pair< int, std::string > IntStringPair;

        m_map.insert( IntStringPair( key, value ) );
    }

    std::string Extract( int key )
    {
        std::string item;

        IntToStringMap::iterator it = m_map.find( key );
        if ( it != m_map.end() )
        {
            item = it->second;

            m_map.erase( key );
        }
        else
        {
            // Not in map: throw an exception
            throw std::invalid_argument( "Key not presenet in map." );
        }

        return item;
    }

    // ...
    // ... other members
    // ...

private:

    typedef stdext::hash_map< int, std::string > IntToStringMap;
    IntToStringMap m_map;
};

</code>

Test like this:

<code>

IntToString map;
map.Insert( 1, "January" );
map.Insert( 2, "February" );
map.Insert( 5, "May" );

cout << map.Extract(5) << endl;
cout << map.Extract(1) << endl;
cout << map.Extract(2) << endl;

</code>

HTH,
Giovanni