Implemented Queue using array

Author: alka-tripathi

src/test/java/com/thealgorithms/datastructures/queues/ImplementQueue.java

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+public class ImplementQueue {
+    // implementation of queue using array
+    // Queue Algorith type:FIFO (First Come First Out)
+
+    // create Queue class
+    public static class Queue {
+        int arr[];
+        int size;
+        int rear;
+
+        public Queue(int n) {
+            arr = new int[n];
+            size = n;
+            rear = -1; // initizalation of the rear
+        }
+
+        // operations
+
+        // IsEmpty() method
+        public boolean isEmpty() {
+            return rear == -1; // when rear will be -1 that means no element is there in the queue
+        }
+
+        public boolean isOverflow() {
+
+            return rear == size - 1;
+        }
+
+        // add() method
+        public void add(int data) {
+            if (isOverflow()) {
+                System.out.println("Queue is full now !!");
+            }
+            rear = rear + 1;
+            arr[rear] = data;
+        }
+
+        // remove() method
+        public int remove() {
+            if (isEmpty()) {
+                System.out.println("Queue is Empty !!");
+                return -1;
+            }
+            int front = arr[0]; // 1 2 3 4 here front will point to 1
+                                // now replacing the 1 to 2 and 2 to 3 and so on..
+            for (int i = 0; i < rear; i++) {
+                arr[i] = arr[i + 1];
+            }
+            rear = rear - 1;
+            return front; // removed element
+        }
+
+        // peek() method
+
+        public int peek() {
+            if (isEmpty()) {
+                System.out.println("No element is there");
+                return -1;
+            }
+            return arr[0];
+        }
+
+    }
+
+    public static void main(String[] args) {
+        Queue q = new Queue(5);
+        q.add(1);
+        q.add(9);
+        q.add(10);
+
+        System.out.println("Front Element:" + q.peek());
+        System.out.println("Removed Element:" + q.remove());
+
+        q.add(90);
+        q.add(100);
+
+        q.add(120);
+        q.add(56);
+        System.out.println(q.isOverflow());
+
+    }
+}