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Added IsEven Function to Maths directory #629

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Merged
raklaptudirm merged 2 commits into from
Jul 3, 2021
Merged

Added IsEven Function to Maths directory #629

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1213574
Added IsEven Function to Maths directory
AbhinavXT Jul 2, 2021
709de83
Added jest file in tests, added description and normal even number t…
AbhinavXT Jul 3, 2021
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56 changes: 56 additions & 0 deletions Maths/IsEven.js
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Original file line number Diff line number Diff line change
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/*
* Even Number: https://simple.wikipedia.org/wiki/Even_number
*
* function to check if number is even
* return true if number is even
* else false
*/

/**
* @param {number} number
* @return {boolean}
*/

/*
* Checking if number is even using divisibility by 2
*
* If number is divisible by 2 i.e remainder = 0, then it is even
* therefore, the function will return true
*
* If number is not divisible by 2 i.e remainder != 0, then it is not even i.e odd
* therefore, the function will return false
*/

export const isEven = (number) => {
return number % 2 === 0
}

/*
* 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 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, which is checked with the use
* of the equality operator.
*
* References:
* https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Bitwise_AND
*/

export const isEvenBitwise = (number) => {
return (number & 1) === 0
}
21 changes: 21 additions & 0 deletions Maths/test/IsEven.test.js
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import { isEven, isEvenBitwise } from '../IsEven'

test('should return if the number is even or not', () => {
const isEvenNumber = isEven(4)
expect(isEvenNumber).toBe(true)
})

test('should return if the number is even or not', () => {
const isEvenNumber = isEven(7)
expect(isEvenNumber).toBe(false)
})

test('should return if the number is even or not', () => {
const isEvenNumber = isEvenBitwise(6)
expect(isEvenNumber).toBe(true)
})

test('should return if the number is even or not', () => {
const isEvenNumber = isEvenBitwise(3)
expect(isEvenNumber).toBe(false)
})