Program To Implement Circular Queue Using Linked List. Code Example

Example: circular queue using linked list in c++

#include<iostream>  #define SIZE 100  using namespace std;  class node { public:     node()     {         next = NULL;     }   int data;   node *next; }*front=NULL,*rear=NULL,*n,*temp,*temp1;  class cqueue { public:     void insertion();     void deletion();     void display(); };  int main() {     cqueue cqobj;   int ch;   do   {      cout<<"\n\n\tMain Menu";      cout<<"\n##########################";      cout<<"\n1. Insert\n2. Delete\n3. Display\n4. Exit\n\nEnter Your Choice: ";      cin>>ch;      switch(ch)      {         case 1:           cqobj.insertion();           cqobj.display();           break;         case 2:           cqobj.deletion();           break;         case 3:           cqobj.display();           break;         case 4:           break;         default:           cout<<"\n\nWrong Choice!!! Try Again.";      }   }while(ch!=4);   return 0; }  void cqueue::insertion() {   n=new node[sizeof(node)];   cout<<"\nEnter the Element: ";   cin>>n->data;   if(front==NULL)   {       front=n;   }   else   {       rear->next=n;   }   rear=n;   rear->next=front; }  void cqueue::deletion() {   int x;   temp=front;   if(front==NULL)   {       cout<<"\nCircular Queue Empty!!!";   }   else   {      if(front==rear)      {        x=front->data;        delete(temp);        front=NULL;        rear=NULL;      }      else      {         x=temp->data;         front=front->next;         rear->next=front;         delete(temp);      }      cout<<"\nElement "<<x<<" is Deleted";      display();   } }  void cqueue::display() {   temp=front;   temp1=NULL;   if(front==NULL)   {     cout<<"\n\nCircular Queue Empty!!!";   }   else   {     cout<<"\n\nCircular Queue Elements are:\n\n";     while(temp!=temp1)     {        cout<<temp->data<<"  ";        temp=temp->next;        temp1=front;     }   } }