fix StatesStack inheritance with DoublyLinkedStack; remove getStateListHead() and use getHead(); overridden output operator (operator<<) for the StateList class;

pr6.cpp

@@ -415,7 +415,7 @@ public:
 };
 
 
-class StateList {
+class StateList : public DoublyLinkedStack<State> {
 protected:
     SinglyLinkedListQueue<State> stateList;
 
@@ -424,8 +424,13 @@ public:
     void addState(const State& state) {
         stateList.push(state);
     }
-    Element<State>* getStateListHead() const {
+    friend ostream& operator<<(ostream& os, const StateList& stateList) {
-        return stateList.getHead();
+        Element<State>* current = stateList.stateList.getHead();
+        while (current != nullptr) {
+            os << current->getInfo() << endl;
+            current = current->getNext();
+        }
+        return os;
     }
 
     // Удаление государства из начала списка
@@ -595,15 +600,7 @@ int main() {
 
     cout << "List of states:" << endl;
     //cout << states->findStateByName("USA") << endl;
-    Element<State>* current = states->getStateListHead();
+    cout << loadedStates << endl;
-    while (current != nullptr) {
-        if (current->getInfo().getName() != "") {
-            cout << "State: " << current->getInfo().getName() << ", Capital: " << current->getInfo().getCapital()
-                << ", Language: " << current->getInfo().getLanguage() << ", Population: " << current->getInfo().getPopulation()
-                << ", Area: " << current->getInfo().getArea() << endl;
-        }
-        current = current->getNext();
-    }
 
     cout << "States with area between 9800500 and 9987263:" << endl;
     states->printStatesByArea(9800500, 9987263);