Iterate over vector of pair

There are at least three errors in the loop.

for ( vector < pair<float,pair<int,int>> >::const_iterator it = edges.begin() ; itt != edges.end; it++){
        cout >> it.first;
    }

First of all you have to use edges.end() instead of edges.end. And inside the body there has to be

    cout << it->first;

instead of

    cout >> it.first;

To escape such errors you could write simply

for ( const pair<float, pair<int,int> > &edge : edges )
{
   std::cout << edge.first;
}

C++14 iterators are a lot simpler

for (const auto& pair : edges)
{
    std::cout << pair.first;
}

C++17 iterators allow deeper access

for (const auto& [first, sec] : edges)
{
    std::cout << first;
}

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