What is Queue? Write an Algorithm for the INSERTION & DELETION operations.

Solution:-
Introduction of Queue:-
   *   Queue is Linear , Non – primitive data structure.
   *   Accessed from two ends                 
                 i.    Rear -> To insert item
                 ii.   Front -> To delete item
   *   Queue operations are:
               i.    Insertion (enque)
               ii.   Deletion (deque)
   *   Working principles First in First out (FIFO).

Algorithm:-
Algorithm to insert item in to linear queue (enque )
enque ( queue [maxsize] , item , rear , front )

             Step 1:- if (rear == maxsize -1)
                                     print " QUEUE OVERFLOW "                        
                           Other wise
                                 Read item
                                 if ( front = =  rear  = = -1)
                                           Set rear = 0
                                           Set front = 0
                                 Other wise                                                
                                           Set rear = rear + 1                                 
                                 End if
                                 Set queue[rear]=item
                                 print " SUCCESS INSERT ITEM "
                         End if             
             Step 2:- stop.


Algorithm to delete item from linear queue ( deque )
Deque (queue [maxsize ] , item , front , rear )

               Step 1:- if( front == -1 )
                                       print " QUEUE UNDERFLOW "
                             Otherwise                                       
                                       Set item = queue [front]
                                       if( rear == front )
                                                  Set front = -1
                                                  Set rear = -1
                                       Otherwise
                                                  Set front = front +1
                                       End if
                                       print " SUCCESS DELETE ITEM "
                              End if
               Step 2:- stop.