While and do-while loops in Kotlin - Mini Project: Build & Apply

Using While and Do-While Loops in Kotlin

📖 Scenario: You are creating a simple program that counts down from a starting number to zero. This is like counting down before a rocket launch or a game timer.

🎯 Goal: Build a Kotlin program that uses a while loop and a do-while loop to count down numbers and print messages.

📋 What You'll Learn

Create a variable called count with the value 5

Create a variable called limit with the value 0

Use a while loop with the condition count > limit to decrease count by 1 each time

Use a do-while loop with the condition count >= limit to print the countdown message

Print the final message "Countdown complete!"

💡 Why This Matters

🌍 Real World

Counting down is common in games, timers, and launching sequences where you need to repeat actions until a condition is met.

💼 Career

Understanding loops is essential for automating tasks, processing data, and controlling program flow in software development.

1

Create the starting count variable

Create a variable called count and set it to 5.

Kotlin

# Create a variable called count and set it to 5
// Your code here

Need a hint?

Use var count = 5 to create a variable that can change.

2

Create the limit variable

Create a variable called limit and set it to 0.

Kotlin

var count = 5
# Create a variable called limit and set it to 0
// Your code here

Need a hint?

Use var limit = 0 to set the stopping point for the countdown.

3

Use a while loop to count down

Use a while loop with the condition count > limit. Inside the loop, decrease count by 1 using count--.

Kotlin

var count = 5
var limit = 0
# Use a while loop with condition count > limit
# Inside the loop, decrease count by 1
// Your code here

Need a hint?

Write while (count > limit) { count-- } to count down.

4

Use a do-while loop to print countdown and final message

Use a do-while loop with the condition count >= limit. Inside the loop, print "Counting down: " + count and decrease count by 1. After the loop, print "Countdown complete!".

Kotlin

var count = 5
var limit = 0
while (count > limit) {
    count--
}
# Use a do-while loop with condition count >= limit
# Inside the loop, print "Counting down: " + count and decrease count by 1
# After the loop, print "Countdown complete!"
// Your code here

Need a hint?

Use do { ... } while (count >= limit) to print and count down including zero.