This function will receive an array of positive integers and it should return a new array with the factorial of each number.

So far I came up with this but it doesn't work and I don't know where is the problem, any ideas?

function getFactorials (nums) {
  let arr = [];
  for(let i = 0; i < nums.length; i++) {
    if(nums[i] <= 1) {
      return 1;
     } else {
      arr.push(nums[i] * getFactorials(nums[i] - 1));
     }
   }
  return arr;
 }

This function will receive an array of positive integers and it should return a new array with the factorial of each number.

So far I came up with this but it doesn't work and I don't know where is the problem, any ideas?

function getFactorials (nums) {
  let arr = [];
  for(let i = 0; i < nums.length; i++) {
    if(nums[i] <= 1) {
      return 1;
     } else {
      arr.push(nums[i] * getFactorials(nums[i] - 1));
     }
   }
  return arr;
 }

• javascript
• arrays
• recursion

• 2 It's easier to solve this task by creating a separate - recursive or not - function for calculating the factorial of a single integer. Then you can just use 'map' to get one array by applying this function to each of its elements. – raina77ow Commented Jan 11, 2018 at 15:10
• 1 this can be as simple as nums.map(factorial) – feihcsim Commented Jan 11, 2018 at 15:15

6 Answers 6

try this use map

var a = [1, 2, 3, 4, 5];

function fact(x) {
   return (x == 0) ? 1 : x * fact(x-1);
}

console.log(a.map(fact));

Try the following:

function getFactorials (nums) {
  let arr = [];
  for(let i = 0; i < nums.length; i++) {
    let j, fact;
    fact=1;
    for(let j=1; j<=nums[i]; j++)  
    {
      fact= fact*j;
    }
    arr.push(fact);
   }
  return arr;
}
let res = getFactorials([5,9])
console.log(res);

Try this way:

function factorial(n) {
  if (n === 0) {
    return 1;
  }
  return n * factorial(n - 1);
}

function getFactorials (nums) {
  let arr = [];
  for(let i = 0; i < nums.length; i++) {
     arr.push(factorial(nums[i]));
  }
  return arr;
}

getFactorials([6,5,3])

const factorial = (n) => {
  let res = [];
  while(n != 0){ 
    //get all integers less than or equal to n
    res.push(n);
    n--;
  }
  return res.reduce((x, y) => {
    return x * y; 
    //reduce the array of integers into a single number via multiplication
  });
}

const nums = [1, 2, 3, 4, 5];

const factorialArr = (arr) => {
  return arr.map(n => {
    //iterate through a list of numbers and return the factorial of each
    return factorial(n);
  });
}

const result = factorialArr(nums);
console.log(result) -> // Array [ 1, 2, 6, 24, 120 ]

function getFactorials(nums) {
    const factNums = nums.map(
        function factorial (num) {
            return (num == 0 ? 1 : num * factorial(num -1));
        }
    )

    return factNums;
}

#include <stdio.h>
int iFactorial(int iCount)
{
    int iProduct = 1;
    int iNumber = 1;
    while (iNumber <= iCount)
    {
            iProduct *= iNumber;
            iNumber++;
    }
    return iProduct;
}
int main(void)
{
    int iFac[10] = {0};
    int iCount = 0;
    for (iCount = 0; iCount < 9; iCount++)
            iFac[iCount] = iFactorial(iCount);
    for (iCount = 0; iCount < 9; iCount++)
            printf("\nThe value of the factorial is %d\n", iFac[iCount]);
    return 0;
}