Hi friends,
i was recently started writing a program on java needed for my practicals
but as i started i found an error which deletes last element of queue
actually i want to delete first element of queue
anybody can solve it
import java.util.*;
class VQueue
{
int size;
int qarr[];
int rear;
int front;
int i;
VQueue(int n)
{
size=n;
qarr=new int[n];
rear=-1;
front=0;
i=0;
}
void insert(int val)
{
rear++;
if(rear==size)
{
System.out.println("Queue is full!! Remove some items...");
rear--;
}
else
{
qarr[rear]=val;
}
}
int remove()
{
int item;
if(rear==-1)
{
System.out.println("Queue is Empty!! Add some items first...");
return 0;
}
else
{
front=0;
item=qarr[front];
front--;
rear--;
return item;
}
}
public void display()
{
int i;
if(rear==-1)
{
System.out.println("Queue is Empty!! Add some items first...");
}
else
{
for(i=0;i<=rear;i++)
{
System.out.println("Queue element "+(i+1)+" : "+qarr[i]);
}
}
}
}//end of class VQueue
class QueueEX
{
public static void main(String args[])
{
Scanner sc=new Scanner(System.in);
System.out.print("Enter size of queue : ");
int n=sc.nextInt();
int item;
VQueue vq=new VQueue(n);
int ch;
do
{
System.out.println("\nMenu:\n1.Insert\n2.Remove\n3.Display\n4.Exit\n");
ch=sc.nextInt();
switch(ch)
{
case 1:
System.out.print("Enter an elemnt to insert in queue : ");
int val=sc.nextInt();
vq.insert(val);
break;
case 2:
item=vq.remove();
System.out.print("Item deleted from queue is : "+item);
break;
case 3:
vq.display();
break;
case 4:
break;
default:
System.out.print("Enter a valid choice");
}
}while(ch!=4);
}
}
front--; is not working as required
