Thread: std::map probs

Hi,

i got following code:

Code:

typedef std::map<int, LPITEMIDLIST> IdIDListMap; 
IdIDListMap map;

so far so good everything works expect that one:

Code:

int index = "SomeNumber";
LPITEMIDLIST lPIDL = map[index];

my compiler says:
Error 1 error C2678: binary '[' : no operator found which takes a left-hand operand of type 'const IdIDListMap' (or there is no acceptable conversion)

as far as i know the operator[] is declared that way:
TYPE& operator[]( key_type& key )
so what am i doing wrong.
Sorry if its horribly stupid or already answered, but i tried searching for sth similiar and gave up after two pages of wrong posts

Code:

int index = "SomeNumber";

This is an error, you can't assign a string literal to an int.


For your map, I wouldn't use the [ ] operator, instead, prefer to use find(), which is a nonmodifying function.

Even if your map isn't declared const, I assume its declared as a member of a class (although perhaps you'd like to confirm where your 'map' comes from), and my guess is that you're probably trying to call this code from a const member function, which isn't allowed to call modifying functions of the map.

try this instead - (untested)

Code:

IdIDListMap::const_iterator iter = map.find(index);
LPITEMIDLIST lPIDL;
if( iter )
    lPIDL = iter->second;

Code:

int index = "SomeNumber";

was just an to show i get some number

//well i already figured out how to use find, but i would love to know why the compiler thinks it is illegal access.
// But thanks for the help.
Nevermind thanks Bench82 its exaclty what you say !