Add bonus problems on recursion

BONUS/Recursion/ArrayProduct/ArrayProd.java

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+/**
+ * Product of array elements using recursion 
+ * @author MadhavBahlMD
+ * @date 18/01/2019
+ */
+
+import java.util.Scanner;
+
+public class ArrayProd {
+    public static double findProduct (double arr[], int n) {
+        if (n <= 0)  return 1;
+        return arr[n-1]*findProduct(arr, n-1);
+    }
+    public static void main(String[] args) {
+        Scanner input = new Scanner (System.in);
+        System.out.println("/* ===== Product of Array elements using recursion ===== */");
+
+        // Input the array
+        System.out.print("\nEnter the number of elements in the array: ");
+        int n = input.nextInt();
+        double arr[] = new double[n];
+        for (int i=0; i<n; i++) {
+            System.out.print("Enter arr[" + i + "]: ");
+            arr[i] = input.nextDouble();
+        }
+
+        // Print the product
+        System.out.println("The product of numbers is: " + findProduct(arr, n));
+    }
+}

BONUS/Recursion/ArrayProduct/README.md

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+# Array Product
+
+WAP to calculate the product of array elements using recursion
+
+**Example**
+
+```
+input: [1, 2, 3, 4, 5]
+output: 120
+```
+
+## Solution
+
+### [JavaScript Implementation](./arrayProd.js)
+
+```js
+/**
+ * Find Product of array elements
+ * @author MadhavBahlMD
+ * @date 18/01/2019
+ */
+
+function findProduct (arr, num) {
+    if (num <= 0)  return 1;
+    return arr[num-1]*findProduct(arr, num-1);
+}
+
+let arr = [2, 3, 4, 5];
+console.log ('Product of elements of [2, 3, 4, 5] is: ', findProduct (arr, arr.length));
+```
+
+### [Java Implementation](./ArrayProd.java)
+
+```java
+/**
+ * Product of array elements using recursion 
+ * @author MadhavBahlMD
+ * @date 18/01/2019
+ */
+
+import java.util.Scanner;
+
+public class ArrayProd {
+    public static double findProduct (double arr[], int n) {
+        if (n <= 0)  return 1;
+        return arr[n-1]*findProduct(arr, n-1);
+    }
+    public static void main(String[] args) {
+        Scanner input = new Scanner (System.in);
+        System.out.println("/* ===== Product of Array elements using recursion ===== */");
+
+        // Input the array
+        System.out.print("\nEnter the number of elements in the array: ");
+        int n = input.nextInt();
+        double arr[] = new double[n];
+        for (int i=0; i<n; i++) {
+            System.out.print("Enter arr[" + i + "]: ");
+            arr[i] = input.nextDouble();
+        }
+
+        // Print the product
+        System.out.println("The product of numbers is: " + findProduct(arr, n));
+    }
+}
+```

BONUS/Recursion/ArrayProduct/arrayProd.js

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+/**
+ * Find Product of array elements
+ * @author MadhavBahlMD
+ * @date 18/01/2019
+ */
+
+function findProduct (arr, num) {
+    if (num <= 0)  return 1;
+    return arr[num-1]*findProduct(arr, num-1);
+}
+
+let arr = [2, 3, 4, 5];
+console.log ('Product of elements of [2, 3, 4, 5] is: ', findProduct (arr, arr.length));

BONUS/Recursion/ArraySum/ArraySum.java

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+import java.util.Scanner;
+
+/**
+ * Recursive Array Sum
+ * @author MadhavBahlMD
+ * @date 18/01/2019
+ */
+
+public class ArraySum {
+    public static int findArraySum (int arr[], int num) {
+        if (num <= 0)  return 0;
+        return arr[num-1] + findArraySum(arr,num-1);
+    }
+
+    public static void main(String[] args) {
+        Scanner input = new Scanner (System.in);
+        System.out.println("/* ===== Sum of Array elements using recursion ===== */");
+
+        // Input the array
+        System.out.print("\nEnter the number of elements in the array: ");
+        int n = input.nextInt();
+        int arr[] = new int[n];
+        for (int i=0; i<n; i++) {
+            System.out.print("Enter arr[" + i + "]: ");
+            arr[i] = input.nextInt();
+        }
+
+        // Print the product
+        System.out.println("The sum of numbers is: " + findArraySum(arr, n));
+    }
+}

BONUS/Recursion/ArraySum/README.md

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+# Array Sum
+
+WAP to calculate the sum of elements in a given integer array using recursion
+
+**Example** 
+
+```
+input: [1, 2, 3, 4, 5]
+output: 15
+```
+
+## Solution
+
+### [JavaScript Implementation](./arraySum.js)
+
+```js
+/**
+ * @author MadhavBahlMD
+ * @date 18/01/2019
+ * Array Elements Sum using Recursion
+ */
+
+function findArraySum (arr, num) {
+    if (num <= 0)   return 0;
+    return arr[num-1] + findArraySum(arr, num-1);
+}
+
+let arr = [1, 2, 3, 4, 5];
+console.log (`Sum of Elements of array ${arr} is: ${findArraySum(arr, arr.length)}`);
+```
+
+### [Java Solution](./ArraySum.java)
+
+```java
+import java.util.Scanner;
+
+/**
+ * Recursive Array Sum
+ * @author MadhavBahlMD
+ * @date 18/01/2019
+ */
+
+public class ArraySum {
+    public static int findArraySum (int arr[], int num) {
+        if (num <= 0)  return 0;
+        return arr[num-1] + findArraySum(arr,num-1);
+    }
+
+    public static void main(String[] args) {
+        Scanner input = new Scanner (System.in);
+        System.out.println("/* ===== Sum of Array elements using recursion ===== */");
+
+        // Input the array
+        System.out.print("\nEnter the number of elements in the array: ");
+        int n = input.nextInt();
+        int arr[] = new int[n];
+        for (int i=0; i<n; i++) {
+            System.out.print("Enter arr[" + i + "]: ");
+            arr[i] = input.nextInt();
+        }
+
+        // Print the product
+        System.out.println("The sum of numbers is: " + findArraySum(arr, n));
+    }
+}
+```

BONUS/Recursion/ArraySum/arraySum.js

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+/**
+ * @author MadhavBahlMD
+ * @date 18/01/2019
+ * Array Elements Sum using Recursion
+ */
+
+function findArraySum (arr, num) {
+    if (num <= 0)   return 0;
+    return arr[num-1] + findArraySum(arr, num-1);
+}
+
+let arr = [1, 2, 3, 4, 5];
+console.log (`Sum of Elements of array ${arr} is: ${findArraySum(arr, arr.length)}`);

BONUS/Recursion/Fibonacci/Fibonacci.java

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+import java.util.Scanner;
+
+/**
+ * Nth element of fibonacci series using recursion
+ * @author MadhavBahlMD
+ * @date 18/01/2019
+ */
+
+public class Fibonacci {
+    public static int findElement (int num) {
+        if (num <= 2)   return 1;
+        return findElement(num-1) + findElement(num-2);
+    }
+
+    public static void main(String[] args) {
+        Scanner input = new Scanner (System.in);
+        System.out.println("/* ===== Fibonacci using recursion ===== */");
+
+        // Take the input
+        System.out.print("\nEnter the value of n: ");
+        int n = input.nextInt();
+
+        // Print the result
+        System.out.println(n + "th number of fibonacci series is: " + findElement(n));
+    }
+}

BONUS/Recursion/Fibonacci/README.md

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+# Fibonacci Series
+
+WAP to find the nth number in fibonacci series using recursion
+
+**Example**
+
+```
+input: 5
+output: 5
+
+input: 7
+output: 13
+```
+
+## Solution
+
+### [JavaScript Solution](./fibonacci.js)
+
+```js
+/**
+ * Fibonacci Series Using Recursion
+ * @author MadhavBahlMD
+ * @date 18/01/2019
+ */
+
+function fibonacci (n) {
+    if (n <= 2) return 1;
+    return fibonacci (n-1) + fibonacci (n-2);
+}
+
+console.log ('7th element in fibonacci series is:', fibonacci(7));
+```
+
+### [Java Solution](./Fibonacci.java)
+
+```java
+import java.util.Scanner;
+
+/**
+ * Nth element of fibonacci series using recursion
+ * @author MadhavBahlMD
+ * @date 18/01/2019
+ */
+
+public class Fibonacci {
+    public static int findElement (int num) {
+        if (num <= 2)   return 1;
+        return findElement(num-1) + findElement(num-2);
+    }
+
+    public static void main(String[] args) {
+        Scanner input = new Scanner (System.in);
+        System.out.println("/* ===== Fibonacci using recursion ===== */");
+
+        // Take the input
+        System.out.print("\nEnter the value of n: ");
+        int n = input.nextInt();
+
+        // Print the result
+        System.out.println(n + "th number of fibonacci series is: " + findElement(n));
+    }
+}
+```

BONUS/Recursion/Fibonacci/fibonacci.js

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+/**
+ * Fibonacci Series Using Recursion
+ * @author MadhavBahlMD
+ * @date 18/01/2019
+ */
+
+function fibonacci (n) {
+    if (n <= 2) return 1;
+    return fibonacci (n-1) + fibonacci (n-2);
+}
+
+console.log ('7th element in fibonacci series is:', fibonacci(7));

BONUS/Recursion/Power/Power.java

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+/**
+ * @author @MadhavBahlMD
+ * @date 18/01/2019
+ */
+
+import java.util.Scanner;
+
+public class Power {
+    public static double findPower (double a, double n) {
+        if (n <= 0)
+            return 1;
+        return a*findPower(a, n-1);
+    }
+
+    public static void main(String[] args) {
+        Scanner input = new Scanner (System.in);
+        System.out.println("/* ===== Exponent ===== */");
+
+        // Input the base and exponent
+        System.out.print("\nEnter a: ");
+        double a = input.nextDouble();
+        System.out.print("Enter n: ");
+        double n = input.nextDouble();
+
+        // Find and print the power
+        double power = findPower(a, n);
+        System.out.println(a + " raised to the power " + n + " is = " + power);
+    }
+}