JavaScript: Compute the factors of a positive integer

JavaScript Function: Exercise-13 with Solution

Compute Factors

Write a JavaScript function to compute the factors of a positive integer.

Sample Solution-1:

JavaScript Code:

// Define a function named factors that returns an array of factors for a given number n
function factors(n) {
 // Initialize an empty array num_factors to store the factors
 var num_factors = [], i;
 // Iterate through numbers from 1 to the square root of n to find factors
 for (i = 1; i <= Math.floor(Math.sqrt(n)); i += 1) { // Check if i is a factor of n if (n % i === 0) { // Push i to the factors array num_factors.push(i); // Check if n divided by i is not equal to i (avoid duplication for perfect squares) if (n / i !== i) // Push n divided by i to the factors array num_factors.push(n / i); } } // Sort the factors array in ascending order using a numeric sort num_factors.sort(function(x, y) { return x - y; }); // Return the sorted array of factors return num_factors; } // Log the result of calling factors with the input number 15 to the console console.log(factors(15)); // [1,3,5,15] // Log the result of calling factors with the input number 16 to the console console.log(factors(16)); // [1,2,4,8,16] // Log the result of calling factors with the input number 17 to the console console.log(factors(17)); // [1,17] 

Output:

[1,3,5,15]
[1,2,4,8,16]
[1,17]

Flowchart:

Live Demo:

See the Pen JavaScript - Compute the factors of a positive integers-function-ex- 13 by w3resource (@w3resource) on CodePen.

Sample Solution-2:

JavaScript Code:

// Define a function named find_Factors that returns an array of factors for a given number num
function find_Factors(num) {
 // Initialize an empty array factors to store the factors
 let factors = [];
 // Loop through all numbers from 1 to num/2 and check if they are a divisor
 for (let i = 1; i <= num / 2; i++) { // Check if i is a factor of num if (num % i === 0) { // If true, push i to the factors array factors.push(i); } } // Add num as a factor factors.push(num); // Return the array of factors return factors; } // Log the result of calling find_Factors with the input number 15 to the console console.log(find_Factors(15)); // Log the result of calling find_Factors with the input number 16 to the console console.log(find_Factors(16)); // Log the result of calling find_Factors with the input number 17 to the console console.log(find_Factors(17)); 

Output:

[1,3,5,15]
[1,2,4,8,16]
[1,17]

Explanation:
The above function takes a positive integer num as input and loops through all numbers from 1 to num/2 to check if they are divisors of the input number. If a number is a divisor, it is added to an array of factors. Lastly, the function returns an array of factors which includes the input number itself.

Flowchart:

Live Demo:

See the Pen javascript-function-exercise-13-1 by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

• Write a JavaScript function that computes all factors of a positive integer using a traditional for loop.
• Write a JavaScript function that computes and returns the factors of a number in sorted order.
• Write a JavaScript function that computes the factors of a number using a recursive approach.
• Write a JavaScript function that computes the factors of a number and filters out those that are prime.

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