Array Conversion Approach

Recursive Approach

This method involves calculating the factorial sequentially and using built-in JavaScript functions to convert the resultant number into an array of digits. The `reduce} method is then used to calculate the sum of these digits, which is straightforward but may result in cost from array formation.

Example: This example demonstrates how to calculate the factorial of a number and then convert it into an array of digits to compute their sum.

Javascript

function factorial(n) {
    let result = 1;
    for (let i = 2; i <= n; i++) {
        result *= i;
    }
    return result;
}
 
function sumOfDigitsInFactorial(num) {
    const fact = factorial(num);
    const digits = Array.from(String(fact),
        Number);
    return digits.reduce((sum, digit) =>
        sum + digit, 0);
}
 
const number = 5;
const sum = sumOfDigitsInFactorial(number);
console.log("Sum of digits in factorial:", sum);

Output

Sum of digits in factorial: 3

JavaScript Program to Find the Sum of Digits in a Factorial

Let’s first define the problem before proceeding to a solution. Any positive number less than or equal to n is the product of all positive integers, and the factorial of a non-negative integer n is denoted by n!. For example, 5!, sometimes known as “five factorial,” is equivalent to 5 × 4 × 3 × 2 × 1 = 120. Adding up the digits of a given number’s factorial is our objective.

Examples:

Input: 10
Output: 27

Input: 100
Output: 648

These are the following appraoches:

Table of Content

Iterative Approach
Recursive Approach
Array Conversion Approach

Tags:

#JavaScript-Program #JavaScript #Web Technologies

Recursive Approach

Array Conversion Approach

Javascript

JavaScript Program to Find the Sum of Digits in a Factorial

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