Exercise
Thursday
## Whiteboard Practice

### Goal

### Problem

### Further Exploration

When and how whiteboarding practice is implemented will be up to your teacher. Below is a recommended prompt.

For this week’s whiteboarding lesson, we’ll focus on using arrays and loops to assess a string.

As the interviewee:

- Ask clarifying questions.
- Keep talking.
- Explain your plan at the beginning; recap what you’ve done at the end.
- Make eye contact.
- Plan your space.

As the interviewer:

- Answer questions as best as you can.
- Be encouraging. Whiteboarding is difficult!
- Be patient. Only offer hints if your partner indicates that they need help.
- Be engaged. Part of this practice is getting used to having someone evaluate your work as your produce it.
- Offer
*constructive*feedback. Find at least one thing that your partner did well*and*one thing they could improve at.

**Prompt 1**: Write a method that takes in an array of numbers and returns an array with all number whose digits add up to an even number removed. The sum of the digits for `13`

is 4, so it would be removed. The sum of the digits for `124`

is 7, so it would not be removed.

**Example**:

- Given: [ 1001, 93, 625, 1, 43, 10, 12, 99, 200]
- Return: [ 625, 1, 43, 10, 12 ]

**Prompt 2**: Write a method that takes in an array of numbers *and* a number (`n`

) and returns the array with the multiples of `n`

removed.

**Example**:

- Given: [ 1, 9, 6, 1, 3, 10, 12, 99, 2] , 3
- Return: [ 1, 1, 10, 2 ]

**Prompt 1**:

- Alter your method such that it takes a second parameter called
`choice`

. If`choice`

is "true", then the method should behave as normal. If`choice`

is`false`

, then numbers whose digets sun to an odd number should be removed. - Alter your method such that it takes a second parameter (n) of type
`number`

. The method should filter the input array to remove all numbers whose digits add up to`n`

.

**Prompt 2**:

Alter your method such that it takes a third parameter called

`choice`

. If`choice`

is "multiples", then the method should behave as normal. If`choice`

is`factors`

, numbers that are factors of`n`

should be removed from the array. (i.e. Given: [ 1, 9, 6, 1, 3, 10, 12, 99, 2] , 12, "factors"; Return: [ 9, 10, 99 ]). You should create a helper method to keep your code organized.Alter your method to accept an array of numbers as the second parameter. Remove the multiples/factors of each of these numbers from the original array and return the filtered array. (i.e. Given: [ 1, 9, 6, 1, 3, 10, 12, 99, 2] , [ 3, 5 ], "multiples"; Return: [ 1, 1, 99, 2 ])