File size: 2,604 Bytes
c574d3a |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 |
// A class to represent a queue
class QueueImplementation {
private int[] arr; // array to store queue elements
private int front; // front points to the front element in the queue
private int rear; // rear points to the last element in the queue
private int capacity; // maximum capacity of the queue
private int count; // current size of the queue
// Constructor to initialize a queue
QueueImplementation(int size) {
arr = new int[size];
capacity = size;
front = 0;
rear = -1;
count = 0;
}
// Utility function to dequeue the front element
public void dequeue() {
// check for queue underflow
if (isEmpty()) {
System.out.println("Underflow\nProgram Terminated");
System.exit(1);
}
System.out.println("Removing " + arr[front]);
front = (front + 1) % capacity;
count--;
}
// Utility function to add an item to the queue
public void enqueue(int item) {
// check for queue overflow
if (isFull()) {
System.out.println("Overflow\nProgram Terminated");
System.exit(1);
}
System.out.println("Inserting " + item);
rear = (rear + 1) % capacity;
arr[rear] = item;
count++;
}
// Utility function to return the front element of the queue
public int peek() {
if (isEmpty()) {
System.out.println("Underflow\nProgram Terminated");
System.exit(1);
}
return arr[front];
}
// Utility function to return the size of the queue
public int size() {
return count;
}
// Utility function to check if the queue is empty or not
public Boolean isEmpty() {
return (size() == 0);
}
// Utility function to check if the queue is full or not
public Boolean isFull() {
return (size() == capacity);
}
}
class Queue {
public static void main(String[] args) {
// create a queue of capacity 5
QueueImplementation q = new QueueImplementation(5);
q.enqueue(1);
q.enqueue(2);
q.enqueue(3);
System.out.println("The front element is " + q.peek());
q.dequeue();
System.out.println("The front element is " + q.peek());
System.out.println("The queue size is " + q.size());
q.dequeue();
q.dequeue();
if (q.isEmpty()) {
System.out.println("The queue is empty");
} else {
System.out.println("The queue is not empty");
}
}
}
|