无法在地图中打印来自 map 的矢量值

Question

I am trying to print out the whole contents of map of maps but keep encountering into issues. Here is my map initialisation map<int, map<int, vector<int>>> myMap;

I have tried the following code:

for( auto const & cit : myMap)
    {
        cout << cit.first << " : ";
        auto const & imap = cit.second;
        for( auto const & cit2 : imap )
        {
            cout << cit2.first << ":" << cit2.second << ","; // errors out
            //cout << cit2.first << ":"; // works, but it is not printing out the vector<int> portion
        }
        cout << endl;
    }

As mentioned above, as soon as cit2.second is used, I got the following error: error: no match for 'operator<<' (operand types are 'std::basic_ostream<char>' and 'const std::vector<int>')|

can someone kindly give me some insights?

Answer 1

You need to do it like this.

for( auto const & cit : myMap)
    {
        cout << cit.first << " : ";
        auto const & imap = cit.second;
        for( auto const & cit2 : imap )
        {
            cout << cit2.first << ":";
            auto const &vec = cit2.second;
            for(auto const &i : vec)
            {
                cout<<i<<" ";
            }cout<<endl;   
            //cout << cit2.first << ":"; // works, but it is not printing out the vector<int> portion
        }
        cout << endl;
    }