Queue | Data Structures

#include<iostream>
using namespace std;

void addqueue();
void deletequeue();
void display();

struct queue
{
 int data;
 struct queue *next;

}*front=NULL,*rear=NULL;

typedef struct queue node;

main()
{

   int choice;
   do
  {
   cout<<"\n 1. Push";
   cout<<"\n 2. Pop ";
   cout<<"\n 3.Display";
   cout<<"\n Enter the choice :";
   cin>>choice;
  
  switch(choice)
 
  {
    case 1 :  addqueue();
              break;
   
    case 2 :  deletequeue();
              break;
   
    case 3 :  display();
              break;
   
    default : cout<<"\n Wrong choice! ";
              break;
  }

 }while(choice>0&&choice<4);


}

void addqueue()
{  
 
  int item;
  node *temp;
  temp=new node;
  cout<<"\n Enter the item to insert : ";
  cin>>temp->data;
  temp->next=NULL;
  if(rear==NULL)
  {  front=temp;
     rear=temp; 
  }
  else
  { rear->next=temp;
    rear=temp;
  }
    

}

void deletequeue()
{
  node *temp;
 
  if(front==NULL)
    cout<<"\n No item in list ";
 
 else if(front==rear)
    {
      cout<<"item deleted is "<<front->data;
      front=NULL;
      rear=NULL;
    }

 else
 {
   temp=front;
   cout<<"\n item popped is "<<temp->data;
   front=front->next;
   delete temp;
 }

}




void display()
{
  node *temp;

 if(front==NULL)
    cout<<"\n No item to display ";
else
 { temp=front;
   cout<<"\n\n";
   while(temp!=rear)
     {
      cout<<"  "<<temp->data;
      temp=temp->next;
     }
    cout<<"  "<<temp->data;
  }
}