DSAimplementations/queue_array.cpp at main · kholiator/DSAimplementations · GitHub

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#include<iostream>
using namespace std;

class Queue{
    private:
    int *queueArray;
    int startIndex;
    int nextIndex;
    int capacity;
    int size;
    void expandArray(){
        int *newArray=new int[capacity*2];
        int index=0;
       for(int i=startIndex;i<capacity;i++){
           newArray[index]=queueArray[i];
           index++;
       }
       for(int i=0;i<startIndex;i++){
           newArray[index]=queueArray[i];
           index++;
       }
        nextIndex=capacity;
        startIndex=0;
        capacity=capacity*2;
        delete[]queueArray;
        queueArray=newArray;
    }

    public:
    Queue(){
        capacity=5;
        queueArray=new int[capacity];
        nextIndex=0;
        size=0;
        startIndex=-1;

    }


    void enqueue(int element){
        if(size==capacity){
            expandArray();
        }
        queueArray[nextIndex]=element;
        nextIndex=(nextIndex+1)%capacity;
        if(startIndex==-1){
            startIndex=0;
        }
        size++;

    }
    int getSize(){
        return size;
    }
    bool isEmpty(){
        if(size==0){
            return true;
        }
        return false;
    }

    int front(){
        if(isEmpty()){
            cout<<"Empty Queue"<<endl;
            return 0;
        }
        return queueArray[startIndex];
    }

    int dequeue(){
         if(isEmpty()){
            cout<<"Empty Queue"<<endl;
            return 0;
        }
        else{
            int ans=queueArray[startIndex];
            startIndex=(startIndex+1)%capacity;
            size--;
            if(size==0){
                startIndex=-1;
                nextIndex=0;
            }
            return ans;

        }

    }


};

int main(){
    Queue q;
    q.enqueue(2);
    cout<<q.getSize()<<endl;
    q.enqueue(3);
    cout<<q.getSize()<<endl;
    q.enqueue(4);
    cout<<q.getSize()<<endl;
    q.enqueue(5);
    cout<<q.getSize()<<endl;
    q.enqueue(6);
    cout<<q.getSize()<<endl;
    q.enqueue(7);
    cout<<q.getSize()<<endl;
    q.enqueue(8);
    cout<<q.getSize()<<endl;
    cout<<q.front()<<endl;
    cout<<boolalpha<<q.isEmpty()<<endl;
    cout<<q.dequeue()<<endl;
    cout<<q.dequeue()<<endl;
    cout<<q.dequeue()<<endl;
    cout<<q.dequeue()<<endl;
    cout<<q.dequeue()<<endl;
    cout<<q.dequeue()<<endl;
    // cout<<q.dequeue()<<endl;
    // cout<<q.dequeue()<<endl;
     q.enqueue(2);
    cout<<q.getSize()<<endl;
    q.enqueue(3);
    cout<<q.getSize()<<endl;
    q.enqueue(4);
    cout<<q.getSize()<<endl;
    q.enqueue(5);
    cout<<q.getSize()<<endl;
    q.enqueue(6);
    cout<<q.getSize()<<endl;
    q.enqueue(7);
    cout<<q.getSize()<<endl;
    q.enqueue(8);
    cout<<q.getSize()<<endl;
    cout<<q.front()<<endl;


}