Queue in C++

#include <stdexcept>

class Node {
   public:
       Node(int value)
           : value(value), next(nullptr)
       {}
       Node(int value, Node* next)
           : value(value), next(next)
       {}
       int value;
       Node* next;
};

class Queue {
   public:
       Queue()
           :size(0), head(nullptr), tail(nullptr)
       {}
       ~Queue();
       bool isEmpty();
       int peek();
       void enqueue(int value);
       int dequeue();
   private:
       Node* head;
       Node* tail;
       int size;
};

Queue::~Queue() {
   Node* tmp = this->head;
   this->tail = nullptr;
   this->size = 0;
   while(tmp != nullptr) {
       Node* deadPtr = tmp;
       tmp = tmp->next;
       delete deadPtr;
   }
   
   this->head = nullptr;
}

bool Queue::isEmpty() {
   return size == 0;
}

int Queue::peek() {
   if(this->isEmpty()) {
       throw std::exception();
   }
   return this->head->value;
}

void Queue::enqueue(int value) {
   if(this->isEmpty()) {
       this->tail = new Node(value);
       this->head = this->tail;
       ++this->size;
   }
   else {
       this->tail->next = new Node(value);
       this->tail = this->tail->next;
       ++this->size;
   }
}

int Queue::dequeue() {
   if(this->isEmpty()) {
       throw std::exception();
   }
   if(this->size == 1) {
       int tmpVal = this->head->value;
       Node* tmp = this->head;
       this->head = nullptr;
       this->tail = nullptr;
       this->size = 0;
       delete tmp;
       return tmpVal;
   }
   else {
       Node* tmp = this->head;
       int tmpVal = tmp->value;
       this->head = this->head->next;
       --this->size;
       delete tmp;
       return tmpVal;
   }
}