# NCERT Solutions for Class 12 Computer Science (C++) – Queue

### Long Answer Type Questions [4 marks each]

Question 1:
Define member function delque() to perform delete operation on a linked queue where each node has the following structure :

```struct node
{
char name
int marks;
};
class queue
{
node *front,‘rear;
public :
queue() {front=rear=NULL;
}
void delque ( );
};    [CBSE Comptt., 2014]```

```void queue : : delque ()
{
if ( front != NULL)
{
node *Temp = front;
cout << Temp -> name << Temp
->marks;
delete Temp;
if(front == NULL)
rear = NULL;
}
else
cout << "Queue is empty";
}
(4 marks for correct program)```

Question 2:
Give the necessary declaration of linked’ implemented Queue containing players information (as defined in the following definition of Node). Also write a user defined function in C++ to delete one Player’s information from the Queue.
[CBSE Comptt., 2013]

```struct node
{
int Player No ;
char PlayerName;
}```

NODE *QUEUEDEL(Node * front, int val, char val2[ ])

```{
Node *temp;
if (front ==NULL)    
cout<<"Queue EMPTY";
{
else
{
temp=front ;
temp®PlayerNo=val;    
strcpy (temp®PlayerName, val2);
delete temp;
}
return (front);
}  ```

Question 3:
Write a function QDELETE ( ) in C++ to perform delete operation on a Linked Queue, which contains Passenger no and Passenger name. Consider the following definition of Node in the code,

```struct node
{
long int Pno;
char Pname ;
};    [O.D, 2013]```

//Function to delete queue elements Node * QUEUE (Node * front, int val, char vail [])

```{
Node *temp;
if (front == NULL)
cout <<"Queue Empty";
else
{
temp = front;
temp®Pno=val;
strcpy (temp®Pname, vail);
delete temp;
}
return (front);
}    ```

Question 4:
Write a function QINSERT() in C+ + to perform insert operation on a Linked Queue, which contains Client no and Client name. Consider the following definition of NODE in the code of . QINSERT ().    [Delhi, 2013]

```struct Node
{
long int Cno; // Client No
char Cname ; //
Client Name
Node *Next ;
};```

Function to Insert element
Node * QINSERT (Node *rear, int val),

```char val []
{
Node *temp;
temp = new Node;
temp®Cno = val;
strcpy (temp®Cname, val);
temp®NEXT=NULL;
rear®NEXT=temp;
rear=temp;
return (rear);
}    ```

Question 5:
Write a function in C++ to perform Insert operation in a circular Queue containing Layer’s information (represented with the help of an array of structure Player).    [CBSE SQP 2013]

```struct Player
{
long PID;    //Player ID
char Pname ;}    //Player Name
}```

```void Insert ( )
{
PLAYER *P = new PLAYER;
cout <<"Enter Player ID & Name";
cin>>P→PID;
gets (P→ Pname);
if ((fronts = NULL) && (rear == NULL))
{
front = rear = P;
}
else
{
rear = P;
}
}    ```

Question 6:
Write a function in C++ to perform insert operation in a static circular queue containing book’s information (represented with the help of an array of structure BOOK).    [O.D, 2012]

```struct BOOK
{
long Accno; //Book Accession Number char Title;    //Book Title
};```

```struct BOOK
{
long Accno; char Title  ;
int front, rear;
}B  ;
void insert()
{
if (r e a r = = s i z e - l & & f r o n t = = 0||front== rear+1)
{
cout<<"\n Circular queue is full"; return;
}
else if(rear==-l)
{
rear++;
front++;
}
else if(rear==size-1)
rear=0;
else
{
rear++;
}
cout<<"Enter Title : ” ;
cin>>B[rear] . Title;
cout<<"Enter Accno : ” ;
cin>>B[rear] . Accno;
}    ```

Question 7:
Write a function in C++ to perform insert operation in a dynamic queue containing DVD’s information (represented with the help of an array of structure DVD). [Delhi, 2012]
/*Function in C++ to perform insert in a dynamic queue is given as*/

```struct DVD
{
long No; // DVD Number
char Title; // DVD Title
};
void insert(struct DVD *start, char data ) ;
{
DVD *q, *temp;
// Dynamic memory has been allocated for a node
temp=(DVD*)malloc(size of (DVD));
temp=Title=data ;
temp"Next=NULL;
if (start    =    = NULL) /*Element
inserted at end*/
while (q"Next ! = NULL)
q=q.Next;
q.Next = temp;
}    ```

Question 8:
Write the definition of a member function INSERT() for a class QUEUE in C++, to insert a CUSTOMER in a dynamically allocated Queue of items considering the following code which is already written as a part of the program,

```struct CUSTOMER
{
int CNO; char CNAME;
};
Class QUEUE
{
CUSTOMER *R,*F;
Public:
QUEUE(){R=NULL;F=NULL;}
void INSERT();
void DELETE()
-QUEUE();
};    [CBSE SQP 2013]```

```void QUEUE : : INSERT ()
{
CUSTOMER*T=New CUSTOMER;
cin>>T>>;
gets(T→CNAME);
//OR cin>>T>>CNAME;
if (R==NULL)
{
F=T; R=T;
}
else
{ R → LINK = T; R = T;
}
}```

(1 Mark for correct a new code)
(1/2 Mark for entering data to new code)
(1/2Mark for assigning NULL to link of the new code)
(1/2 Mark for assigning front to the first code as L=T)
(1/2 Mark for linking the last node to new code as R→Link=T)
(1 Mark for assign Read to the new code as R=T)

+