Printing containers.md

Printing vector in forward & reverse order

vector<int>     vArr(arr, arr+N);
std::for_each(vArr.begin(), vArr.end(), [](int a){cout<<a<<" ";}); // Forward
std::for_each(vArr.rbegin(), vArr.rend(), [](int a){cout<<a<<" ";}); // Reverse

Printing map in forward & reverse order

for_each(map.begin(),map.end(),[](pair<const string,Node> &pair) 
{
  cout<<pair.first<<endl;
  cout<<pair.second<<endl;
});

Note: first template parameter of pair in lambda function should be const.