Problem with iterator for vector of lists in c++

dmatador

For a function

using namespace std;

mst(const vector<list<pair<int,int> > > &adj_lists, int v){
// code before iterator
list<pair<int,int> >:: iterator it;
it = adj_list[0].begin();
// code after
}

I'm trying to set up an iterator to walk through the list contained within adj_list[0], but the code above gives me a compiler error about there not being a match for "operator=". Am I wrong in believing that the vector should contain the starting point of the list? Thanks for any help.



*** hey everyone while waiting for responses I figured out the solution.
I should have been using

list<pair<int,int> >:: const_iterator it;

instead of

list<pair<int,int> >:: iterator it;

thanks to anyone who considered it.

Hurkyl

Let's see.

adj_list is of type const vector<list<pair<int,int> > > &

Therefore, adj_list[0] is of type vector<list<pair<int,int> > >::const_reference, which ought to be of type const list<pair<int,int> > &.

Therefore, adj_list[0].begin() is of type list<pair<int,int> >::const_iterator

And since you generally cannot implicitly convert Container::const_iterator into Container::iterator, the compiler rightfully complains!

Coin

Ah, iterator vs const_iterator distinctions.

C++1x needs to hurry up so we can use "auto" already :(