For loop with index (withIndex) in Kotlin - Mini Project: Build & Apply

Using For Loop with Index in Kotlin

📖 Scenario: You are managing a small bookstore inventory. You want to list all the books with their position numbers to organize the shelves.

🎯 Goal: Build a Kotlin program that uses a for loop with withIndex() to print each book's position and title.

📋 What You'll Learn

Create a list called books with the exact titles: "The Hobbit", "1984", "Pride and Prejudice"

Create a variable called totalBooks to store the number of books

Use a for loop with withIndex() to iterate over books

Inside the loop, create a string called bookEntry that combines the index (starting from 1) and the book title

Add a final line that stores the last bookEntry in a variable called lastEntry

💡 Why This Matters

🌍 Real World

Listing items with their positions is common in inventory management, menus, and reports.

💼 Career

Understanding loops with indexes helps in data processing, UI lists, and database record handling.

1

Create the books list

Create a list called books with these exact titles: "The Hobbit", "1984", and "Pride and Prejudice".

Kotlin

# Create the list of books
# Your code here

Need a hint?

Use listOf to create the list with the exact book titles.

2

Add totalBooks variable

Create a variable called totalBooks that stores the number of books in the books list.

Kotlin

val books = listOf("The Hobbit", "1984", "Pride and Prejudice")
# Create totalBooks to hold the size of books
# Your code here

Need a hint?

Use books.size to get the number of items in the list.

3

Use for loop with withIndex()

Use a for loop with withIndex() to iterate over books. Inside the loop, create a string called bookEntry that combines the index (starting from 1) and the book title separated by a dot and space. For example, "1. The Hobbit".

Kotlin

val books = listOf("The Hobbit", "1984", "Pride and Prejudice")
val totalBooks = books.size
# Use for loop with withIndex() to create bookEntry
# Your code here

Need a hint?

Use for ((index, book) in books.withIndex()) and inside the loop create bookEntry with "${index + 1}. $book".

4

Store the last bookEntry

Add a variable called lastEntry outside the loop. Inside the loop, update lastEntry to the current bookEntry. This will keep the last book entry after the loop finishes.

Kotlin

val books = listOf("The Hobbit", "1984", "Pride and Prejudice")
val totalBooks = books.size
var lastEntry = ""
for ((index, book) in books.withIndex()) {
    val bookEntry = "${index + 1}. $book"
    # Update lastEntry here
    # Your code here
}

Need a hint?

Declare lastEntry as an empty string before the loop. Inside the loop, assign lastEntry = bookEntry.