fix build errors

pr6.cpp

@@ -1,35 +1,46 @@
 #include <iostream>
+#include <stdexcept>
+
 using namespace std;
 
 template<class T>
-class Element
-{
+class Element {
 protected:
     Element* next;
-    Element* prev;
     T info;
 
 public:
-    Element(T data) : next(nullptr), prev(nullptr), info(data) {}
-    Element(Element* Next, Element* Prev, T data) : next(Next), prev(Prev), info(data) {}
-    Element(const Element& el) : next(el.next), prev(el.prev), info(el.info) {}
+    Element() : next(nullptr), info(T()) {}
+    Element(const T& data) : next(nullptr), info(data) {}
+    Element(Element* Next, const T& data) : next(Next), info(data) {}
+    Element(const Element& el) : next(el.next), info(el.info) {}
 
     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;
 };
 
 template<class T1>
-ostream& operator<<(ostream& s, const Element<T1>& el)
-{
+ostream& operator<<(ostream& s, const Element<T1>& el) {
     s << el.info;
     return s;
 }
 
 template<class T>
-class LinkedList
-{
+class LinkedList {
 protected:
     Element<T>* head;
     Element<T>* tail;
@@ -39,20 +50,15 @@ public:
     LinkedList() : head(nullptr), tail(nullptr), count(0) {}
 
     virtual Element<T>* pop() = 0;
-    virtual Element<T>* push(T value) = 0;
-    virtual Element<T>& operator[](int index) = 0;
+    virtual Element<T>* push(const T& value) = 0;
 
-    virtual bool isEmpty() { return count == 0; }
+    bool isEmpty() { return count == 0; }
 
-    template<class T1>
-    friend ostream& operator<<(ostream& s, const LinkedList<T1>& list);
-
-    virtual ~LinkedList()
-    {
-        cout << "\nBase class destructor";
+    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;
         }
@@ -61,46 +67,25 @@ public:
     }
 };
 
-template<class T1>
-ostream& operator<<(ostream& s, const LinkedList<T1>& list)
-{
-    Element<T1>* current = list.head;
-    while (current != nullptr) {
-        s << *current << " ";
-        current = current->next;
-    }
-    return s;
-}
-
-template<class T, int N = 20>
-class Stack : public LinkedList<T>
-{
+template<class T>
+class SinglyLinkedListStack : public LinkedList<T> {
 public:
-    Stack() : LinkedList<T>()
-    {
-        if (N > 0) {
-            for (int i = 0; i < N; i++)
-                this->push(0);
-        }
-    }
+    SinglyLinkedListStack() : LinkedList<T>() {}
 
-    virtual Element<T>* push(T value)
-    {
-        if (this->head == nullptr) { // if(count==0)
-            this->tail = new Element<T>(value);
-            this->head = this->tail;
+    virtual Element<T>* push(const T& value) override {
+        Element<T>* newElement = new Element<T>(value);
+        if (this->head == nullptr) {
+            this->head = this->tail = newElement;
         }
         else {
-            this->tail->next = new Element<T>(value);
-            this->tail->next->prev = this->tail;
-            this->tail = this->tail->next;
+            this->tail->setNext(newElement);
+            this->tail = newElement;
         }
         this->count++;
-        return this->tail;
+        return newElement;
     }
 
-    virtual Element<T>* pop()
-    {
+    virtual Element<T>* pop() override {
         if (this->tail == nullptr)
             return nullptr;
 
@@ -110,28 +95,90 @@ public:
             this->head = this->tail = nullptr;
         }
         else {
-            this->tail = this->tail->prev;
-            this->tail->next = nullptr;
+            Element<T>* current = this->head;
+            while (current->getNext() != this->tail) {
+                current = current->getNext();
+            }
+            this->tail = current;
+            current->setNext(nullptr);
         }
 
         this->count--;
         return res;
     }
 
-    virtual ~Stack() { cout << "\nStack class destructor"; }
+    virtual ~SinglyLinkedListStack() { cout << "\nSinglyLinkedListStack class destructor\n"; }
 };
 
-int main()
-{
-    if (true)
-    {
-        Stack<double, 20> S;
-        for (int i = 0; i < 10; i++)
-            S.push(i);
-        // S.insert(3.5, S.head->next->next->next); // insert method not defined in the provided code
-        cout << S;
-        cout << "\n";
-        // cout<<S.Find_R(5.5, S.head); // Find_R method not defined in the provided code
+template<class T>
+class SinglyLinkedListQueue : public LinkedList<T> {
+public:
+    SinglyLinkedListQueue() : LinkedList<T>() {}
+
+    virtual Element<T>* push(const T& value) override {
+        Element<T>* newElement = new Element<T>(value);
+        if (this->head == nullptr) {
+            this->head = this->tail = newElement;
+        }
+        else {
+            this->tail->setNext(newElement);
+            this->tail = newElement;
+        }
+        this->count++;
+        return newElement;
     }
+
+    virtual Element<T>* pop() override {
+        if (this->head == nullptr)
+            return nullptr;
+
+        Element<T>* res = this->head;
+
+        if (this->head == this->tail) {
+            this->head = this->tail = nullptr;
+        }
+        else {
+            this->head = this->head->getNext();
+        }
+
+        this->count--;
+        return res;
+    }
+
+    virtual ~SinglyLinkedListQueue() { cout << "\nSinglyLinkedListQueue class destructor\n"; }
+};
+
+template<class T>
+class StackQueue : protected SinglyLinkedListStack<T>, protected SinglyLinkedListQueue<T> {
+public:
+    StackQueue() : SinglyLinkedListStack<T>(), SinglyLinkedListQueue<T>() {}
+
+    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() {
+    StackQueue<int> stackQueue;
+
+    // Добавление элементов в конец и начало списка
+    stackQueue.push_back(1);
+    stackQueue.push_back(2);
+    stackQueue.push_front(3);
+    stackQueue.push_front(4);
+
+    // Удаление элементов с начала и конца списка
+    while (!stackQueue.isEmpty()) {
+        Element<int>* elem = stackQueue.pop_back();
+        if (elem) {
+            cout << elem->getInfo() << " ";
+            delete elem;
+        }
+    }
+    cout << endl;
+
     return 0;
 }