cpp-practice/58_queue/2_queue_using_ll/queue_ll.cpp at main · AwesomeSam9523/cpp-practice · GitHub

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class Node {
public :
    int data;
    Node *next;

    Node(int data) {
        this->data = data;
        next = nullptr;
    }
};

class Queue {
    // Define the data members
    Node *head;
    Node *tail;
    int size;


public:
    Queue() {
        // Implement the Constructor
        head = nullptr;
        tail = nullptr;
        size = 0;
    }

    /*----------------- Public Functions of Stack -----------------*/

    int getSize() {
        // Implement the getSize() function
        return size;
    }

    bool isEmpty() {
        // Implement the isEmpty() function
        return size == 0;
    }

    void enqueue(int data) {
        // Implement the enqueue() function
        Node *newNode = new Node(data);
        if(head == nullptr) {
            head = newNode;
            tail = newNode;
            size++;
            return;
        }
        tail -> next = newNode;
        tail = newNode;
        size++;
    }

    int dequeue() {
        // Implement the dequeue() function
        if(head == nullptr) {
            return -1;
        }
        int data = head -> data;
        Node *temp = head;
        head = head -> next;
        size--;
        delete temp;
        return data;


    }

    int front() {
        // Implement the front() function
        if(head == nullptr) {
            return -1;
        }
        return head -> data;
    }
};