Re: [Mingw-users] Delete an element in a map while iterate on it

[Linlin Y. <yan...@gm...>]

TSalm,

This is a much general C++ question rather than that about MinGW. I
think the newsgroup comp.lang.c++ would be better.

It is not safe to delete an element of a map before using the iterator
pointing to it. One of my methods may like this:

for (map<string, string> it = myMap.begin(); it != myMap.end(); )
{
    if (it->first == "2") // condition for deleting
    {
        map<string, string> toDel = it;
        it++;
        myMap.erase(toDel);
    }
    else
    {
        it++;
    }
}

On Thu, Sep 10, 2009 at 4:44 AM, TSalm<TS...@fr...> wrote:
> Hi,
>
> I'm not sure it's the correct list for my question since it relates to a
> C++ question... Don't hesitate to sound me off if it's not :-)
>
> Here is my question : is there a way to delete an element of a map while
> iterate on it ?
>
> Here is my code :
> /* ---------------- CODE -------------- */
> #include <stdio.h>
>
> #include <map>
> #include <string>
>
> using namespace std ;
>
> int main( )
> {
>   map<string,string> myMap;
>
>   myMap["1"] = "Un";
>   myMap["2"] = "Deux";
>   myMap["3"] = "Trois";
>   myMap["4"] = "Quatre";
>
>
>   for (map<string,string>::iterator it = myMap.begin();
> it!=myMap.end(); ++it)
>   {
>      string key     = (*it).first;
>      string value   = (*it).second;
>      printf("%s - %s \n" , key.c_str() , value.c_str() );
>
>      if ( key == "2" )
>      {
>         printf("Delete key 2 !\n")  ;
>         myMap.erase( it ) ;
>      }
>   }
>
>   return 0;
> }
> /* ------------------- END CODE --------------------*/
>
> Thanks in advance,
> TSalm
>
>
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