JavaScript: Check whether a number is even or not

JavaScript Function: Exercise-7 with Solution

Write a JavaScript program to check whether a number is even or not.

Visual Presentation:

Sample Solution:

Using recursion:

JavaScript Code:

// Recursive JavaScript function to check if a number is even.
function is_even_recursion(number) {
  // If the number is negative, convert it to its absolute value.
  if (number < 0) {
    number = Math.abs(number);
  }

  // Base case: If the number is 0, it's even.
  if (number === 0) {
    return true;
  }

  // Base case: If the number is 1, it's odd.
  if (number === 1) {
    return false;
  } else {
    // Recursive case: Subtract 2 from the number and recursively check the new number.
    number = number - 2;
    return is_even_recursion(number);
  }
}

// Example usage: Check if certain numbers are even.
console.log(is_even_recursion(234)); // true
console.log(is_even_recursion(-45)); // false
console.log(is_even_recursion(65));  // false 

Output:

true
false
false

Flowchart:

Live Demo:

See the Pen javascript-recursion-function-exercise-7 by w3resource (@w3resource) on CodePen.

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