#include <iostream>#include <string> // for strings - real ones#include <map> // for the mapusing namespace std;// For the needed polymorphism, we'll define a simple base "action".// The interface consists of just the "operator()", which lets us treat objects// as if they were functions.struct Action {  virtual operator() () = 0;};struct HelloAction : Action {  operator() () { cout << "y helo thar 2u2 lolz!!!11" << endl; }}// Now we can already do something like:// HelloAction ha;// ha(); // the object behaves like a function.// Now let's set up a map:map<string, Action> actions;// We construct a HelloAction, and store it in the map.// The map stores things by key; given a key, we can find the matching value. action.insert("hello", HelloAction());// Later, we can check a given string:string userInput; cin << userInput;// Look for the key in the map.map<string, Action>::iterator item = actions.find(userInput);if (item == actions.end()) {  // this means that the key was not found. Therefore "default" handling  // goes here} else {  // the "item" is an iterator pointing at the (key, value) pair stored in the  // map. Thus "item->second" gives us the stored value that corresponds to  // the key - for us, this means the Action object. Then, we "invoke" that  // object via the operator().  item->second();}