Queues implementaion using link list in c++

Queue is a list of elements in which insertions are at one end of the list called rear end and the deletions are at the other end of the list called FRONT end.
Insertion is also known as Enqueue,deletion is also known as Dequeue.

  
    /******************************************************************************
Author: Sunil Kumar
Website: www.techdoon.com
Description: Queues implementaion using link list in c++
*******************************************************************************/
#include<iostream>
#include<cstdlib>
#include<memory>
using namespace std;
void menu();
struct node{
       int info;
       struct node *link;
       };
class queue{
      private:
                 struct node *front,*rear;
      public: 
             queue(); //constructor
             void insert(); //inserting element to the que
             void delet(); //removing elements from the que
             int isEmpty(); //Checking for empty
             void display(); //to fatch the data
       };
queue::queue() //constructor initializing variables
{
             front=rear=NULL;
              }
int queue::isEmpty()
{
               if(front==NULL)                                                   
                return 1;
                else
                return 0;
    }

void queue::insert()
{
     struct node *temp;
     int item;
     cout<<"\nITEM: "; cin>>item;
     temp=new node;
     temp->info=item;
     temp->link=NULL;
     if(front==NULL)
     {
                     front=temp;
                     }
                     else
                     {
                         rear->link=temp;
                         }
                         rear=temp;
     cout<<"\nNew item is inserted to the Queue!!!";
 }
 void queue::delet()
 {
      struct node *temp;
      int item,i;
      if((i=isEmpty())==1) cout<<"UNDERFLOW";
      else 
      {
           item=front->info;
           temp=front;
           front=temp->link;
           cout<<"\n "<<item<<"is Deleted.";
       }
  }
 int main()
 {
     menu();
     cin.get();
     return 0;
 }
void menu()
{
     queue obj;
     int ch;
     while(1)
     {
             cout<<"\n1.INSERT.\n2.DELETE.\n3.DISPLAY.\n0.EXIT.";
             cin>>ch;
             switch(ch)
             {
                       case 1: obj.insert();
                            break;
                       case 2: obj.delet();
                            break;
                       case 3:obj.display();
                       case 0:exit(0);
                       default:
                               cout<<"INVALID.";
                     }
             }
 
 }
void queue:: display()
{
    
     if(front==NULL){
                      cout<<"QUEUE is Empty.";
                      menu();
                      }
     else{
     while(front!=NULL){
     cout<<front->info<<"  ";
     front=front->link;
     }
     menu();
     }
 }
  
    

Posted in: C++,Code

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