Merge pull request #15 from Jacob3075/dsa-14-queue

Added code for Queue

Author: swapnita-pandey

Queue/Queue.kt

@@ -0,0 +1,81 @@
+import java.util.Scanner
+
+class Queue {
+    var front = 0
+    var rear = 0
+    var capacity = 0
+    lateinit var queue: IntArray
+
+    private fun enqueue(data: Int) {
+        if (capacity == rear) {
+            println("Queue is full")
+            return
+        }
+        queue[rear] = data
+        rear++
+        return
+    }
+
+    private fun dequeue() {
+        if (front == rear) {
+            println("Queue is empty")
+            return
+        }
+
+        for (i in 0 until rear - 1) queue[i] = queue[i + 1]
+
+        // store 0 at rear indicating there's no element
+        if (rear < capacity) queue[rear] = 0
+
+        // decrement rear
+        rear--
+        return
+    }
+
+    private fun display() {
+        if (front == rear) {
+            println("Queue is Empty")
+            return
+        }
+        println("Queue: ")
+        var i = front
+        while (i < rear) {
+            print("${queue[i]} ")
+            i++
+        }
+        println()
+        return
+    }
+
+    private fun front() {
+        if (front == rear) {
+            println("Queue is Empty")
+            return
+        }
+        println("Front Element is: ${queue[front]}")
+        return
+    }
+
+    fun main(args: Array<String>) {
+        val sc = Scanner(System.`in`)
+        rear = 0
+        front = rear
+        capacity = 6
+        queue = IntArray(capacity)
+        println("Enter number of elements to be added: ")
+        val n = sc.nextInt()
+        println("Enter the element to Enqueue: ")
+        // adding element to rear of queue
+        for (i in 0 until n) {
+            val s = sc.nextInt()
+            enqueue(s)
+        }
+        display()
+        dequeue()
+        dequeue()
+        display()
+        front()
+        display()
+        sc.close()
+    }
+}