Question

C++ Help
Create a node class/struct.
Create a queue class/struct.
Members:
Node - a node that tracks the front of the queue.
Node - a node that tracks the end of the queue.
Count - indicates how many items are on the queue.
Methods:
En-queue
- Accepts a number and adds to the end of the queue.
De-queue
- Returns a number from the front of the queue.
- If the queueis empty, emit an error indicating the queueis empty.
IsEmpty
- Returns a boolean indicating if the queue is empty.

Answer 1

#include <iostream>

using namespace std;

class Node    //class that represent the node
{

public:

int data;
    //data part of node
Node* next; //this is link part pointing to next node
};

class queue
{

private:

   Node* front;//node indicating front of queue
   Node* end;
//node indicating end of queue
int count; //count indicating no.of elements in queue

public:

queue()
//constructor of queue class intializing front,end to null and count to zero as the queue is empty intially
   {

       front = NULL;

       end = NULL;

       count = 0;

   }
void Enqueue(int element)//this method is used to add elements to queue
    {

       Node* tmp = new Node();
       // Creating a new node
to add the element in it
        tmp->data = element;

       tmp->next = NULL;

       if ( isEmpty() ) //checking if the queue is empty
         {

  
           front = end = tmp;//add the first elemnt and since it is the one and only element it is both front and end
       }

       else {

         
           end->next = tmp;//add this element at end
           end = tmp;
//make this as end
       }

       count++;//increment count as the element is added
   }
int Dequeue()//this method removes the element from front of the queue
   {
     if ( isEmpty() )//checks if queue is empty
         {

           cout<<"Queue is Empty";

           return -1;

         }

       int num = front->data;

       Node* tmp = front;

     

       front = front->next;// Move the front pointer to next node

       count--;//decrement count as a number is deleted from queue
       return num;

   }
    




   bool isEmpty()//function to check wether the queue is empty
   {

     if (count==0)//if count is zero it returns true indicating queue is empty else returns false
      return true;

    else

      return false;

   }

};

int main()

{

   queue q;//create an object to queue class
   int ch;

   int d;

do

   {

     cout<<"\nEnter your choice\n1:Add an element to queue\n2:delete an element from queue\n3:exit\n";

     cin>>ch;
   
switch(ch)//basing on given chice switch to the cases
     
{
       
case 1:

//if choice is 1 ask for the number and call Enqueue function
          cout<<"enter the number you want to add to queue:";

        int n;

          cin>>n;

         q.Enqueue(n);

          cout<<"element added to queue\n";

         break;
      
case 2:
//if choice is 2 call deque function and store the return value in d
           d=q.Dequeue();

           if(d==-1)

            cout<<"queue is empty";

        else
          

          cout<<"the element removed from queue is:",d;
         

           break;
      
case 3:
  
       break;
      
default :
         
cout<<"invalid choice, please choose correct number\n";
     
}

}while(ch!=3);
//this loop ends when ch==3
return 0;

}

Sample Output:

Enter your choice
1:Add an element to queue
2:delete an element from queue
3:exit
1
enter the number you want to add to queue:20
element added to queue

Enter your choice
1:Add an element to queue
2:delete an element from queue
3:exit
1
enter the number you want to add to queue:45
element added to queue

Enter your choice
1:Add an element to queue
2:delete an element from queue
3:exit
1
enter the number you want to add to queue:89
element added to queue

Enter your choice
1:Add an element to queue
2:delete an element from queue
3:exit
2
the element removed from queue is:20
Enter your choice
1:Add an element to queue
2:delete an element from queue
3:exit
3