JavaScript: Test if a number is a Harshad Number or not

JavaScript Math: Exercise-90 with Solution

Check Harshad Number

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

In recreational mathematics, a harshad number in a given number base, is an integer that is divisible by the sum of its digits when written in that base.
Example: Number 200 is a Harshad Number because the sum of digits 2 and 0 and 0 is 2 (2+0+0) and 200 is divisible by 2. Number 171 is a Harshad Number because the sum of digits 1 and 7 and 1 is 9(1+7+1) and 171 is divisible by 9.

Test Data:
(113) -> false
(171) -> true
(200) -> true

Sample Solution:

JavaScript Code:

/**
 * Function to check if a number is a Harshad number or not.
 * @param {number} n - The number to be checked.
 * @returns {boolean} - True if the number is a Harshad number, false otherwise.
 */
function test(n) {
  // Convert the number to a string
  n = n.toString();
  // Initialize the total sum of digits
  var total = 0;
  // Loop through each digit of the number
  for (var i = 0; i < n.length; i++) {
    // Add each digit to the total sum
    total += parseInt(n[i]);
  }
  // Convert the number back to an integer
  n = parseInt(n);
  // Check if the number is divisible by the total sum of its digits
  if (n % total === 0) {
    // If divisible, return true
    return true;
  }
  // If not divisible, return false
  return false;
}

// Test cases
// Test if the number 113 is a Harshad number
n = 113;
console.log("n = " + n);
console.log("Test the said number is Harshad Number or not! " + test(n));

// Test if the number 171 is a Harshad number
n = 171;
console.log("n = " + n);
console.log("Test the said number is Harshad Number or not! " + test(n));

// Test if the number 200 is a Harshad number
n = 200;
console.log("n = " + n);
console.log("Test the said number is Harshad Number or not! " + test(n));

Output:

n = 113
Test the said number is Harshad Number or not! false
n = 171
Test the said number is Harshad Number or not! true
n = 200
Test the said number is Harshad Number or not! true

Flowchart:

Live Demo:

See the Pen javascript-math-exercise-90 by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

• Write a JavaScript function that determines if a number is a Harshad number by summing its digits and checking divisibility.
• Write a JavaScript function that converts a number to a string, computes the digit sum, and tests divisibility.
• Write a JavaScript function that handles edge cases such as zero and negative numbers when checking for Harshad numbers.
• Write a JavaScript function that returns a boolean indicating if a number is Harshad and logs the intermediate digit sum.

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