Queue using user defined Exception Handling

24.WAJP to implement a Queue, using user defined Exception Handling (also make use of throw, throws).

Program:

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import java.util.scanner;

class ExcQueue extends Exception
{
  ExcQueue(String S)
  {
    super(S);
  }
}

class Queue
{
 int front,rear;

 int q[]=new int[10];

 Queue
 {
   rear=-1;
  
   front=-1;
 }
void enqueue(int n) throws ExcQueue
{
 if(rear==9)
  
   throw new ExcQueue("queue is full");
 
  rear++;
  
  q[rear]=n;
 
  if(front==-1)
  
   front=0;
}
int dequeue() throws ExcQueue
{
  if(front==-1)
   
    throw new ExcQueue("queue is empty");
  
  int temp=q[front];
 
  if(front==rear)
   
    front=rear=-1;
 
  else
   
    front++;
    
    return(temp);
}

}   

class UseQueue
{
  public static void main(String[] args)
  {
    Queue a=new Queue();
   
    try
    {
      a.enqueue(5);
     
      a.enqueue(20);
   
    }catch(ExcQueue e)
     {
       System.out.println(e.getMessage());
     }
     try
     {
       System.out.println(a.dequeue());
      
       System.out.println(a.dequeue());
      
       System.out.println(a.dequeue());
    
     }catch(ExcQueue e)
      {
        System.out.println(e.getMessage());
      }
  }
}