Odd and Even in JavaScript

Determining whether a number is odd or even is a common task in programming. In JavaScript, there are multiple ways to accomplish this. Two commonly used methods are:

1. Using the least significant bit.
2. Using the modulo operator.

Using the Least Significant Bit

In binary representation, the least significant bit (LSB) of a number is the rightmost bit. For any binary number, if the LSB is 1, the number is odd; if it's 0, the number is even.

Here's how you can implement this in JavaScript:

function isEvenLSB(num) {
  return (num & 1) === 0;
}

function isOddLSB(num) {
  return (num & 1) === 1;
}

console.log(isEvenLSB(4)); // Output: true
console.log(isOddLSB(4)); // Output: false
console.log(isEvenLSB(7)); // Output: false
console.log(isOddLSB(7)); // Output: true

Using the Modulo Operator

Another common method is using the modulo operator (%). When you divide a number by 2, if the remainder is 0, the number is even; otherwise, it's odd.

function isEvenModulo(num) {
  return num % 2 === 0;
}

function isOddModulo(num) {
  return num % 2 !== 0;
}

console.log(isEvenModulo(4)); // Output: true
console.log(isOddModulo(4)); // Output: false
console.log(isEvenModulo(7)); // Output: false
console.log(isOddModulo(7)); // Output: true

Both methods are efficient and commonly used. Choose the one that suits your coding style and requirements best!