Question

Solve in C++ program.

Modify the use of queue data structure such that the array used to implement the queue is dynamically allocated for a fast food autoservice

Answer 1

Array implementation of queue data structure

#include<bits/stdc++.h>
using namespace std; 
#define MAX_SIZE 101 
class queue_implementation
{
private:
    int array[MAX_SIZE];
    int front, rear; 
public:
     //constructor implemenatation to set intial value of front and rear 
    queue_implementation()
    {
        front = -1; 
        rear = -1;
    }
    //check if queue is empty 
    bool IsEmpty()
    {
    
        return (front == -1 && rear == -1); 
    }
    //check if queue reach its maximum size 
    bool IsFull()
    {
        return (rear+1)%MAX_SIZE == front ? true : false;
    }

    // Inserts an element in queue at rear end
    void insert_element (int x)
    {
        cout<<"Inseted element is : "<<x<<" \n";
        if(IsFull())
        {
            cout<<"Error: Queue is Overflow \n";
            return;
        }
        if (IsEmpty())
        { 
            front = rear = 0; 
        }
        else
        {
            rear = (rear+1)%MAX_SIZE;
        }
        array[rear] = x;
    }

    //dequue element at the queue implemenatation
    void remove_element ()
    {
        cout<<" Element Removed after Dequeing : "<<  "\n";
        if(IsEmpty())
        {
            cout<<"Error: Queue is Underflow\n";
            return;
        }
        else if(front == rear ) 
        {
            rear = front = -1;
        }
        else
        {
            front = (front+1)%MAX_SIZE;
        }
    }
    // Returns element at front of queue. 
    int Front()
    {
        if(front == -1)
        {
            cout<<"Error: cannot return front from empty queue\n";
            return -1; 
        }
        return array[front];
    }
   //traverse from rear to front
    void traverse()
    {
        // Finding number of elements in queue  
        int count = (rear+MAX_SIZE-front)%MAX_SIZE + 1;
        cout<<"Queue       : ";
        for(int i = 0; i <count; i++)
        {
            int index = (front+i) % MAX_SIZE; 
            cout<<array[index]<<" ";
        }
        cout<<"\n\n";
    }
};
int main()
{
   queue_implementation queue;
   cout<<"After Enqueueing : \n";
   queue.insert_element (1);   
   queue.insert_element (2);   
   queue.insert_element (3); 
   queue.insert_element (4);   
   queue.insert_element (5);
   queue.insert_element (6);   
   queue.insert_element (7);   
   queue.insert_element (8); 
   queue.insert_element (9);   
   queue.insert_element (10);
   queue.traverse();
   cout<<"After dequeing 2 elements : "<<endl;
   queue.remove_element();
   queue.remove_element();
   queue.traverse(); 
}

output_screen