$3$: Given an CircularArrayQueue class implementing a queue using an array:

class CircularArrayQueue

$\{$

private: int array$[10]$; $//$size is $10$

int front; $//$index of item to dequeue

int back; $//$index of item to enqueue

public: CircularArrayQueue$()$ : array $\{0\},$ front$(0),$ back$(9)\{\}$

void enqueue$($int i$)$;

int dequeue$()$;

$...\}$;

Match the blanks with the corresponding code for void enqueue$($int i$)$ and int dequeue$()$:

void CircularArrayQueue::enqueue$($int i$)$

$\{$

if$(\_\_\_\_$A$\_\_\_\_)$

$\{$

$\_\_\_\_$B$\_\_\_\_$;

array$[$back$]=$i;

$\}$

$\}$

int CircularArrayQueue::dequeue$()$

$\{$

int val $=-1$;

if$(\_\_\_\_$C$\_\_\_\_)$

$\{$

val $=$ array$[$front$]$;

$\_\_\_\_$D$\_\_\_\_$;

$\}$

return val;