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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