While Loop

Part of the Fundamentals section of Coddy's Ruby journey. Lesson 40 of 88.

The for loop works great when you know exactly how many times to repeat. But what if you want to keep looping until a certain condition changes? That's where the while loop comes in.

A while loop continues running as long as its condition remains true:

count = 1
while count <= 3
  puts count
  count += 1
end

This outputs 1, 2, and 3. The loop checks the condition before each iteration. Once count becomes 4, the condition count <= 3 is false, and the loop stops.

The key difference from a for loop is that you control when the loop ends by changing a variable inside the loop. If you forget to update the variable, the loop runs forever! Here's a countdown example:

num = 5
while num > 0
  puts num
  num -= 1
end
puts "Done!"

This counts down from 5 to 1, then prints "Done!" after the loop finishes. The while loop is especially useful when you don't know in advance how many iterations you'll need.

Challenge

Easy

Read a number n from input. Use a while loop to print all numbers from n down to 1, each on its own line. After the countdown finishes, print Blastoff! on a new line.

The input will be a single integer representing the starting number for the countdown.

For example, if the input is 5, the output should be:

5
4
3
2
1
Blastoff!

Try it yourself

# Read the starting number
n = gets.chomp.to_i

# TODO: Write your code below
# Use a while loop to print numbers from n down to 1
# Then print the exact text from the instructions