fix build errors

pr6.cpp

@@ -18,6 +18,18 @@ public:
     template<class T1>
     friend ostream& operator<<(ostream& s, const Element<T1>& el);
 
+    const T& getInfo() const {
+        return info;
+    }
+
+    Element* getNext() const {
+        return next;
+    }
+
+    void setNext(Element* nextElement) {
+        next = nextElement;
+    }
+
     template<class T1> friend class LinkedList;
 };
 
@@ -40,13 +52,13 @@ public:
     virtual Element<T>* pop() = 0;
     virtual Element<T>* push(const T& value) = 0;
 
-    virtual bool isEmpty() { return count == 0; }
+    bool isEmpty() { return count == 0; }
 
     virtual ~LinkedList() {
         cout << "\nBase class destructor\n";
         Element<T>* current = head;
         while (current != nullptr) {
-            Element<T>* nextElement = current->next;
+            Element<T>* nextElement = current->getNext();
             delete current;
             current = nextElement;
         }
@@ -66,7 +78,7 @@ public:
             this->head = this->tail = newElement;
         }
         else {
-            this->tail->next = newElement;
+            this->tail->setNext(newElement);
             this->tail = newElement;
         }
         this->count++;
@@ -84,11 +96,11 @@ public:
         }
         else {
             Element<T>* current = this->head;
-            while (current->next != this->tail) {
-                current = current->next;
+            while (current->getNext() != this->tail) {
+                current = current->getNext();
             }
             this->tail = current;
-            current->next = nullptr;
+            current->setNext(nullptr);
         }
 
         this->count--;
@@ -109,7 +121,7 @@ public:
             this->head = this->tail = newElement;
         }
         else {
-            this->tail->next = newElement;
+            this->tail->setNext(newElement);
             this->tail = newElement;
         }
         this->count++;
@@ -126,7 +138,7 @@ public:
             this->head = this->tail = nullptr;
         }
         else {
-            this->head = this->head->next;
+            this->head = this->head->getNext();
         }
 
         this->count--;
@@ -141,10 +153,12 @@ class StackQueue : protected SinglyLinkedListStack<T>, protected SinglyLinkedLis
 public:
     StackQueue() : SinglyLinkedListStack<T>(), SinglyLinkedListQueue<T>() {}
 
-    Element<T>* push_back(const T& value) { return this->push(value); }
-    Element<T>* push_front(const T& value) { return this->push(value); }
-    Element<T>* pop_back() { return this->pop(); }
-    Element<T>* pop_front() { return this->pop(); }
+    Element<T>* push_back(const T& value) { return SinglyLinkedListQueue<T>::push(value); }
+    Element<T>* push_front(const T& value) { return SinglyLinkedListStack<T>::push(value); }
+    Element<T>* pop_back() { return SinglyLinkedListStack<T>::pop(); }
+    Element<T>* pop_front() { return SinglyLinkedListQueue<T>::pop(); }
+
+    using LinkedList<T>::isEmpty;
 };
 
 int main() {
@@ -158,7 +172,11 @@ int main() {
 
     // Удаление элементов с начала и конца списка
     while (!stackQueue.isEmpty()) {
-        cout << *(stackQueue.pop_back()) << " ";
+        Element<int>* elem = stackQueue.pop_back();
+        if (elem) {
+            cout << elem->getInfo() << " ";
+            delete elem;
+        }
     }
     cout << endl;