for loop inside a function being called in another function's for loop javascript

Question

I'm trying to implement selection sort with javascript, but it seems that either i'm missing something or doing something absolutely wrong.
as you may understand from a first look, sortArray() seems to return arr with only one value 5 while it should return an array with as such [5,5,5,5,5,5].
worth mentioning is that when I comment line smallest_index = find_smallest(nums)
I get the supposed input; [5,5,5,5,5,5].

let nums = [2, 1, 3, 4, 5, 6];

function sortArray(nums) {
  let arr = new Array();
  let smallest_index;
  for (i = 0; i < nums.length; i++) {
    smallest_index = find_smallest(nums);
    arr.push("5");
  }

  return arr;
}

function find_smallest(arr) {
  let smallest = arr[0];
  let smallest_index = 0;

  for (i = 1; i < arr.length; i++) {
    if (arr[i] < smallest) {
      console.log("this");
      smallest = arr[i];
      smallest_index = i;
    }
  }
  return smallest_index;
}

console.log(sortArray(nums));

any help or thoughts as to what i may be not be realizing or doing ?

Make i a local variable in each function. find_smallest() is updating the variable i that's used in sortArray(), so the loop ends after the first iteration. — Barmar
– Barmar, Commented Jul 1, 2022 at 23:32
@Barmar works! thanks for pointing that out, seems i had forgotten let exists for a reason :) — Exodus Reed
– Exodus Reed, Commented Jul 1, 2022 at 23:36

kdiv · Accepted Answer · 2022-07-01 23:41:53Z

1

The problem is within your for loops. More specifically, you need to declare the variable i before using it. If you alter your code like the below snippet, then your code works just as expected:

let nums = [2, 1, 3, 4, 5, 6];

function sortArray(nums) {
  let arr = new Array();
  let smallest_index;
  for (let i = 0; i < nums.length; i++) {
    smallest_index = find_smallest(nums);
    arr.push("5");
  }

  return arr;
}

function find_smallest(arr) {
  let smallest = arr[0];
  let smallest_index = 0;

  for (let i = 1; i < arr.length; i++) {
    if (arr[i] < smallest) {
      console.log("this");
      smallest = arr[i];
      smallest_index = i;
    }
  }
  return smallest_index;
}

console.log(sortArray(nums));

The only difference is using

for (let i = 1; ...

instead of

for (i = 1; ...

answered Jul 1, 2022 at 23:41

kdiv

112 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

for loop inside a function being called in another function's for loop javascript

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related