Val for immutable references in Kotlin - Mini Project: Build & Apply

Val for immutable references

📖 Scenario: Imagine you are creating a simple program to store information about a book. You want to make sure that the book's title does not change once it is set.

🎯 Goal: Learn how to use val in Kotlin to create an immutable reference for a variable.

📋 What You'll Learn

Create a variable using val to hold a book title

Assign the exact string "Kotlin Basics" to the variable

Try to change the value of the variable (this will be explained)

Print the value of the variable

💡 Why This Matters

🌍 Real World

In real apps, using <code>val</code> helps keep important data safe and predictable, like user names or IDs that should not change.

💼 Career

Understanding <code>val</code> is essential for Kotlin developers to write reliable and bug-free code.

1

Create an immutable variable with val

Create a variable called bookTitle using val and assign it the string "Kotlin Basics".

Kotlin

// Create a val variable called bookTitle and assign "Kotlin Basics"
// Your code here

Need a hint?

Use val to make the variable immutable. For example: val name = "value".

2

Try to change the val variable

Add a line below that tries to assign "Advanced Kotlin" to bookTitle.

Kotlin

val bookTitle = "Kotlin Basics"
// Try to change bookTitle to "Advanced Kotlin" here
// Your code here

Need a hint?

Try writing bookTitle = "Advanced Kotlin". Kotlin will not allow this because bookTitle is immutable.

3

Print the value of the val variable

Write a println statement to print the value of bookTitle.

Kotlin

val bookTitle = "Kotlin Basics"
// bookTitle = "Advanced Kotlin" // This line will cause an error if uncommented
// Print bookTitle below
// Your code here

Need a hint?

Use println(bookTitle) to show the value on the screen.

4

Run and observe the output

Run the program and observe the output. It should print Kotlin Basics.

Kotlin

val bookTitle = "Kotlin Basics"
// bookTitle = "Advanced Kotlin" // This line will cause an error if uncommented
println(bookTitle)
// Run the program to see the output

Need a hint?

The program prints the value of bookTitle. Since it is immutable, it stays as Kotlin Basics.