Exercise Tuesday

Goal: In the Looping with for lesson, we learned:

  • The three parameters of a for loop
  • The length property in JavaScript
  • How to use a for loop both with and without arrays

Practice utilizing for loops in a variety of ways by completing the exercises detailed below.

Warm Up

  • What is the difference between for and forEach() loops? Describe to your partner a specific case in which you would use one over the other.
  • How does a for loop 'know' when to stop looping?
  • What else can we do with the first parameter in a for loop?


Count Up By

Create a program that takes two numbers - one to count to and another to determine what multiple to use to get there.

Here is some sample input:
Count to: 30
Count by: 5
Output: 5, 10, 15, 20, 25, 30

Count to: 50
Count by: 7
Output: 7, 14, 21, 28, 35, 42, 49

Don't forget to consider how to handle any input that might be submitted:

  • empty values (user just presses enter)
  • non-numeric values (It may be helpful to read up about the numerical value, NaN)
  • negative numbers
  • count by number is larger than the count to numbers

Turn forEach() into For

Go back through the looping practice problems, and redo one of them with a for loop instead of a forEach() loop.

Word Puzzle

Create a website that uses a method to replace vowels in a string with the dash symbol "-" to create a word puzzle to solve. Hide the original string when you show the resulting word puzzle, so that another person can try and guess it.


String Input: "Believe you can and you're halfway there. Theodore Roosevelt"

Puzzle Output: "B-l--v- y-- c-n -nd y--'r- h-lfw-y th-r-. Th--d-r- R--s-v-lt"

Do this without "regular expressions".

Peer Code Review

  • Is the business logic and user interface logic distinctly separate?
  • Are variable names descriptive and in lower camelCase?
  • Does the code have proper indentation and spacing throughout?
  • Are for loops being used correctly?
  • Are forEach()loops being used correctly?