JavaScript Program to Check Even Number

Posted in JavaScript Tutorial

Updated on Jan 11, 2024

By Mari Selvan

👁️ 126 - Views

⏳ 4 mins

💬 1 Comment

Photo Credit to CodeToFun

🙋 Introduction

In the realm of programming, dealing with numbers is a fundamental task. One common requirement is checking whether a given number is even or not. An even number is an integer that is exactly divisible by 2 without leaving a remainder.

In this tutorial, we will explore a JavaScript program designed to check whether a given number is even. The program involves using the modulo operator to determine if the number is divisible by 2.

📄 Example

Let's delve into the JavaScript code that accomplishes this task.

isEven.html

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<!DOCTYPE html>
<html>
<body>

<script>
// Function to check if a number is even
function isEven(number) {
  // If the remainder is zero, the number is even
  return number % 2 === 0;
}

// Driver program
// Replace this value with the number you want to check
const number = 10;

// Call the function to check if the number is even
if (isEven(number)) {
  console.log(`${number} is an even number.`);
} else {
  console.log(`${number} is not an even number.`);
}
</script>

</body>
</html>

💻 Testing the Program

To test the program with different numbers, modify the value of number in the code.

Output

10 is an even number.

🧠 How the Program Works

The program defines a function isEven that takes a number as input and returns true if the number is even, and false otherwise.
Replace the value of number in the main program with the desired number you want to check.
The program calls the isEven function and prints the result using console.log.

📏 Between the Given Range

Let's take a look at the JavaScript code that checks even numbers and outputs them in the specified range.

isEven.js

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// Function to check if a number is even
function isEven(number) {
  return number % 2 === 0;
}

// Function to find even numbers in the range
function findEvenNumbersInRange(start, end) {
  let evenNumbers = [];

  for (let i = start; i <= end; i++) {
    if (isEven(i)) {
      evenNumbers.push(i);
    }
  }

  return evenNumbers;
}

// Driver program
// Define the range
const startRange = 1;
const endRange = 10;

// Call the function to find even numbers in the range
const evenNumbersInRange = findEvenNumbersInRange(startRange, endRange);

// Output the result
console.log(`Even numbers in the range ${startRange} to ${endRange}:`);
console.log(evenNumbersInRange.join(' '));

💻 Testing the Program

Output

Even numbers in the range 1 to 10:
2 4 6 8 10

Run the script to see the even numbers in the range from 1 to 10.

🧠 How the Program Works

The program defines a function isEven that checks if a given number is even.
It then defines a function findEvenNumbersInRange that iterates through a specified range and collects even numbers.
The main part of the program sets the range from 1 to 10 and outputs the even numbers in that range.