queue1.cpp

queue1.cpp

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// Link to Challenge: https://www.w3resource.com/cpp-exercises/queue/index.php
// Missing: Check if it is full

#include <iostream>
#include <vector>

using namespace std;

class Queue{
    private:

        struct node{
            int data;
            node* next;
        };

        node* head = nullptr;

        bool isLinked = false;

    public:

        Queue(){

        }

        Queue(std::vector<int> arr){
            enqueue(arr);
        }

        void enqueue(std::vector<int> arr){
            node* pointing = nullptr;
            node* tmp = nullptr;
            for (int i = 0; i < arr.size(); i++){
                if (head == nullptr){
                    head = new node{arr[i], nullptr};
                }
                else if (isLinked == false){
                    pointing = new node{arr[i], nullptr};
                    head -> next = pointing;
                    isLinked = true;
                }
                else {
                    tmp = new node{arr[i], nullptr};
                    pointing -> next = tmp;
                    pointing = pointing -> next;
                }
            }
        }

        void dequeue(){
            if (is_empty()){
                return;
            }
            else {
                node* tmp = head;
                head = head -> next;
                delete tmp;
            }
        }

        bool is_empty(){
            return (head == nullptr);
        }

        void print(){
            cout << "Queue Elements: ";
            for (node* i = head; i != nullptr; i = i -> next){
                cout << i -> data << " ";
            }
            cout << endl;
        }

        node* top(){
            return head;
        }


};

int main(){
    Queue q1({5, 2, 3, 1, 4, 7, 9});
    q1.print();
    q1.dequeue();
    q1.print();
    cout << "Top: " + to_string(q1.top() -> data) << endl;
    cout << "Is it empty?: " + to_string(q1.is_empty()) << endl;
    return 0;
}

Console Output

Queue Elements: 5 2 3 1 4 7 9 
Queue Elements: 2 3 1 4 7 9
Top: 2
Is it empty?: 0

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