Data-Structures/queue.java at master · ishitasinghal/Data-Structures · GitHub

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//implementing queue by array
//deletion takes place from the front
classQueue
{
intfront, rear, size;
intlength;
intarray[];

Queue(intlength)
 {
this.length = length;
front = this.size=0;
rear= length-1;
array = newint[this.length];
 }

//checking if Queue doesn't have more space left.
booleanisfull(Queueq)
 {
return(q.size==q.length);
 }

//checking if the queue is Empty.
booleanisempty(Queueq)
 {
return(q.size==0);
 }

//enqueue function to insert the elemnrs in the queue
voidenqueue(intelement)
 {
if(isfull(this))
return;
this.rear = (this.rear + 1)%this.length;
this.array[this.rear] = element;
this.size = this.size + 1;
System.out.println(element+ " enqueued to queue");
 }

//dequeue function queue to delete an element
intdequeue()
 {
if(isempty(this))
returnInteger.MIN_VALUE;
intelement = this.array[this.front];
this.front = (this.front+1)%this.length;
this.size = this.size=1;
returnelement;
 }

//getting the front of the queue
intfront()
 {
if(isempty(this))
 {
returnInteger.MIN_VALUE;
 }
returnthis.array[this.front];
 }

//getting the rear of the queue
intrear()
 {
if(isempty(this))
 {
returnInteger.MIN_VALUE;
 }
returnthis.array[this.rear];
 }
}
publicclassMainc
{
publicstaticvoidmain(Stringargs[])
 {
Queueq = newQueue(500);
q.enqueue(1);
q.enqueue(2);
q.enqueue(3);
q.enqueue(4);
q.enqueue(5);
q.enqueue(6);
q.enqueue(7);
q.enqueue(8);
q.enqueue(9);

System.out.println("## BEFORE ##");
System.out.println( q.front()+ "Front element");
System.out.println("Rear element"+q.rear());
System.out.println("## AFTER ##");
q.dequeue();
q.dequeue();
System.out.println("Front element"+q.front());
System.out.println("Rear element"+q.rear());
 }
}