merge: Improved IsOdd function (TheAlgorithms#914)

fahimfaisaal · web-flow · commit 98c46b4d9e9e · 2022-03-04T16:34:33.000+05:30
* refactor: used Boolean function for conversion

* feat: added one more function and test cases

* test: refactor test case &amp; fixed var names

* chore: fixed test placeholder
diff --git a/Maths/IsOdd.js b/Maths/IsOdd.js
@@ -1,9 +1,45 @@
 /*
- * function to check if number is odd
- * return true if number is odd
+ * Odd Number: https://simple.wikipedia.org/wiki/Odd_number
+ * function to check if number is odd.
+ * return true if number is odd.
  * else false
  */
 
-export const isOdd = (value) => {
-  return !!((value & 1))
-}
+/**
+ * @function isOdd
+ * @description -> Checking if number is odd using not divisibility by 2
+ * If number is not divisible by 2 i.e remainder = 1, then it is odd
+ * therefore, the function will return true
+ *
+ * If number is divisible by 2 i.e remainder != 1, then it is even
+ * therefore, the function will return false
+ * @param {number} number
+ * @returns {boolean}
+ */
+const isOdd = (number) => Boolean(number % 2) // 1 -> true, 0 -> false
+/**
+ * @function isOddBitwise
+ * @description -> Checking if number is even using bitwise operator
+ * Bitwise AND (&) compares the bits of the 32
+ * bit binary representations of the number and
+ * returns a number after comparing each bit:
+ *
+ * 0 & 0 -> 0
+ * 0 & 1 -> 0
+ * 1 & 0 -> 0
+ * 1 & 1 -> 1
+ *
+ * For every odd numbers, the last binary bit will be 1
+ * and for even numbers, the last binary bit will be 0.
+ *
+ * As the number is compared with one, all the
+ * other bits except the last will become 0. The
+ * last bit will be 0 for even numbers and 1 for
+ * odd numbers.
+ * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Bitwise_AND
+ * @param {number} number
+ * @returns {boolean}
+*/
+const isOddBitwise = (number) => Boolean(number & 1) // 1 -> true, 0 -> false
+
+export { isOdd, isOddBitwise }
diff --git a/Maths/test/IsOdd.test.js b/Maths/test/IsOdd.test.js
@@ -0,0 +1,25 @@
+import { isOdd, isOddBitwise } from '../IsOdd'
+
+describe('Testing the isOdd function', () => {
+  it('should return true, if the number is odd', () => {
+    const isOddNumber = isOdd(4)
+    expect(isOddNumber).toBe(false)
+  })
+
+  it('should return true, if the number is odd', () => {
+    const isOddNumber = isOdd(7)
+    expect(isOddNumber).toBe(true)
+  })
+})
+
+describe('Testing the isOddBitwise function', () => {
+  it('should return true, if the number is odd', () => {
+    const isOddNumber = isOddBitwise(6)
+    expect(isOddNumber).toBe(false)
+  })
+
+  it('should return true, if the number is odd', () => {
+    const isOddNumber = isOddBitwise(3)
+    expect(isOddNumber).toBe(true)
+  })
+})
