Page 550 - Computer science 868 Class 12
P. 550

Ans.  (A–B)/C*(D+E)
                     =(–AB)/C*(+DE)
                     =(/–ABC)*(+DE)
                     =*/–ABC+DE
                  3.  A double ended queue is a linear data structure which enables the user to add and remove integers from either ends i.e., from
                    front or rear. The details of the class deQueue are given below:                           [ISC 2023]
                    Class name                                    :   deQueue
                    Data members/instance variable:
                    Qrr[]                                         :   array to hold integer elements
                    lim                                           :   maximum capacity of the dequeue
                    front                                         :   to point the index of the front end
                    rear                                          :   to point the index of the rear end
                    Methods/Member functions:
                    deQueue(int I)                                :   constructor to initialise lim = 1, front = 0 and rear = 0
                    void add Front(int v)                         :    to  add  integers  in  the  dequeue  at  the  front  end  if  possible,
                                                                    otherwise display the message “OVERFLOW FROM FRONT”
                    void add Rear(int v)                          :    to  add  integers  in  the  dequeue  at  the  rear  end  if  possible,
                                                                    otherwise display the message “OVERFLOW FROM REAR”
                     int popFront()                               :    removes  and  returns  the  integers  from  the  front  end  of  the
                                                                    dequeue if any, else returns-999
                    int popRear()                                 :    removes and  returns  the integers from the rear  end of the
                                                                    dequeue if any, else returns-999
                    void show()                                   :   displays the elements of the dequeue
                    (i)   Specify the class deQueue giving details of the functions void addFront(int) and int popFront(). Assume that the other
                       functions have been defined.
                         The main() function and algorithm need NOT be written.
                Ans. class deQueue
                    {
                    int Qrr[];
                    int lim, front, rear;
                    ….
                    void addFront(int a)
                    {
                    if(front==0)
                    System.out.println(“OVERFLOW FROM FRONT”);
                    else
                    Qrr[--front]=a;
                    }
                    int popFront( )
                    {
                    if(front==rear)
                    return -999;
                    else
                    return Qrr[front++];
                    }
                    }
                    (ii)   Differentiate between a stack and a queue.                                          [ISC 2023]
                Ans.  Stack follows LIFO order where as Queue follows FIFO order.
                  4. (i)    A linked list is formed from the objects of the class given below:                 [ISC 2023]
                       Class Node
                       {
                       double sal;
                       Node next;
                       }
                       Write and Algorithm OR a Method to add a node at the end of an existing linked list. The method declaration is as follows:
                       void addNode(Node ptr, double ss)

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