This is beginner level. I am trying to create separate arrays for odd and even numbers from the parent array. Below the code:

const arr = [22, 33, 44, 55, 66]
let even = []
let odd = []



function separateArray(arr) {

    let j, k

    for( let i = 0; i < arr.length; i++ ) {

        if( arr[i]%2 === 0 ){

            even[j] = arr[i]
            j++

        }else {

            odd[k] = arr[i]
            k++

        }
        
    }   
}

separateArray(arr)

for( let i = 0; i < even.length; i++ ) {

    console.log(even[i])

}

I tried calling the function separateArray and then log the even numbers in the console. But it doesn’t display anything.

>Solution :

The reason why you are not seeing anything in the console is because you have not initialized the values of j and k.
In JavaScript, accessing an undefined variable will result in a ReferenceError. You need to initialize j and k to 0 before using them as array indices:

const arr = [22, 33, 44, 55, 66];
let even = [];
let odd = [];

function separateArray(arr) {
  let j = 0,
    k = 0;
  for (let i = 0; i < arr.length; i++) {
    if (arr[i] % 2 === 0) {
      even[j] = arr[i];
      j++;
    } else {
      odd[k] = arr[i];
      k++;
    }
  }
}

separateArray(arr);

for (let i = 0; i < even.length; i++) {
  console.log(even[i]);
}