Question

I have tried all possibilities I could, and failed to find solution. Please help

I want to remove records in vector in map while iterating over it.

map < string, vector < record> >::iterator map_it;
for(map_it = map_records.begin(); map_it != map_records.end(); ++map_it){
    vector < record>::iterator vec_it;
    for(vec_it = (*map_it).second.begin(); vec_it != (*map_it).second.end();){
        if(condition){
            cout << (*map_it).second.size() << endl;
            vec_it = map_it->second.erase(vec_it);
            cout << (*map_it).second.size()<< endl;
        } else {
            ++vec_it;
        }
    }
}

I tried something like this,
(*map_it).second.erase(vec_it)
It give some long number if I query the size of it and program ends with segmentation fault

OUTPUT:
18446744073709551615
18446744073709551615
Segmentation fault

Any help appreciated

Answer 1

   vec_t = map_it->second.erase(vec_it); //note the assignment!

You also need to check it’s validity immediately, so better re-write the inner loop as:

for(vec_it = (*map_it).second.begin(); vec_it != (*map_it).second.end(); )
{
    if(condition)
        vec_it = map_it->second.erase(vec_it);
    else
      ++vec_it;
}