Add day 43

Author: MadhavBahl

README.md

@@ -70,6 +70,7 @@ Motivate yourself to code daily till 60 days, and see the magic! Coding will bec
 | [Day 40](./day40) | [Prefix, Infix, Postfix Conversion](./day40) | [http://codetoexpress.tech/dc/day40/](http://codetoexpress.tech/dc/day40/) | **Intermediate** |
 | [Day 41](./day41) | [Implement Queue Data Structure](./day41) | [http://codetoexpress.tech/dc/day41/](http://codetoexpress.tech/dc/day41/) | **Beginner** |
 | [Day 42](./day42) | [Alternate Queue Combination](./day42) | [http://codetoexpress.tech/dc/day42/](http://codetoexpress.tech/dc/day42/) | **intermediate** |
+| [Day 43](./day43) | [Queue Reversal](./day43) | [http://codetoexpress.tech/dc/day43/](http://codetoexpress.tech/dc/day43/) | **intermediate** |
 
 ## [More Problems](./BONUS/README.md)
 

day42/README.md

@@ -24,7 +24,7 @@ combined queue:
 
 ## JavaScript Implementation
 
-### [Solution](./JavaScript/queue.js)
+### [Solution](./JavaScript/alternateQueue.js)
 
 ```js
 class Queue {

day43/JavaScript/queueReversal.js

@@ -0,0 +1,118 @@
+/**
+ * Queue reversal 
+ * @author MadhavBahlMD
+ * @date 15/02/2019
+ * Method 
+ *  - Dequeue the elements from queue and keep pushing them in stack
+ *  - Pop the elements from stack and enqueue them in the original queue
+ */
+
+// Class declaration for queue data structure
+class Queue {
+    constructor (size) {
+        this.capacty = size;
+        this.data = [];
+        this.frontIndex = 0;
+        this.rearIndex = 0;
+    }
+
+    front () {
+        return data[this.frontIndex];
+    }
+
+    rear () {
+        return data[this.rearIndex];
+    }
+
+    enqueue (element) {
+        if (this.rearIndex >= this.capacty)  {
+            console.log ("Overflow!");
+            return -1;
+        }
+        this.data.unshift (element);
+        // console.log (element + ' added to the queue');
+        this.rearIndex++;
+    }
+
+    dequeue (element) {
+        if (this.rearIndex === 0) {
+            console.log ("Underflow!");
+            return -1;
+        }
+        // console.log (this.data[this.rearIndex -1] + ' has been removed from the queue');
+        this.rearIndex--;
+        return this.data.pop ();
+    }
+
+    displayQueue () {
+        let toBeDisplayed = '-> ';
+        for (let element of this.data) {
+            toBeDisplayed += element + ' -> ';
+        }
+        console.log (toBeDisplayed);
+    }
+}
+
+// Class declaration for stack data structure
+class Stack {
+    // constructor to initialize the stack and it's capacity
+    constructor (limit) {
+        this.myStack = [];
+        this.top = limit;
+    }
+
+    // isEmpty method to check whether the stack is empty
+    isEmpty () {
+        if (this.myStack.length === 0)  return true;
+        else return false;
+    }
+
+    // isFull method to check whether the stack is full
+    isFull () {
+        if (this.myStack.length === this.top)  return true;
+        else return false;
+    }
+
+    // push method to add a record to the stack
+    push (record) {
+        if (!this.isFull()) {
+            console.log (`Pushing ${record} to the stack!`);
+            this.myStack.push (record);
+        } else {
+            console.log ('Sorry! The Stack is full!');
+        }
+    }
+
+    // pop method to remove an element from the stack
+    pop () {
+        if (!this.isEmpty()) {
+            console.log (`Popped element is: ${this.myStack[this.myStack.length-1]}`);
+            return this.myStack.pop ();
+        } else {
+            console.log ('Sorry! The Stack is empty');
+        }
+    }
+
+    // peek method to view the top element
+    peek () {
+        console.log (`Current element is: ${this.myStack[this.myStack.length - 1]}`);
+    }
+}
+
+const reverse = (myQueue) => {
+
+};
+
+const myQueue = new Queue (4);
+
+myQueue.enqueue (1);
+myQueue.enqueue (2);
+myQueue.enqueue (3);
+myQueue.enqueue (4);
+
+console.log ("\n/* ===== Displaying Initial Queue ===== */");
+myQueue.displayQueue();
+
+
+console.log ("\n/* ===== Displaying Final Queue ===== */");
+myQueue.displayQueue();

day43/README.md

@@ -0,0 +1,31 @@
+![cover](./cover.png)
+
+# Day 43 - Queue Reversal
+
+Write a program to reverse the given queue.
+
+#### Hint
+
+Use stack as an intermediate data structure
+
+## Example:
+
+```
+Input:
+    q1  -> 4 -> 3 -> 2 -> 1 ->
+
+Output:
+    q1  -> 1 -> 2 -> 3 -> 4 ->
+```
+
+![ques](./ques.png)
+
+## Solution
+
+## JavaScript Implementation
+
+### [Solution](./JavaScript/queueReversal.js)
+
+```js
+To Be Added
+```