Type inference by the compiler in Kotlin - Mini Project: Build & Apply

Type inference by the compiler

📖 Scenario: You are creating a simple Kotlin program to understand how the compiler can guess the type of variables without you telling it explicitly.

🎯 Goal: Build a Kotlin program that shows how the compiler infers types for different variables and prints their values.

📋 What You'll Learn

Create variables without specifying their types explicitly

Assign values of different types to these variables

Print the values of these variables

💡 Why This Matters

🌍 Real World

Type inference helps programmers write cleaner and faster code by letting the compiler figure out types automatically.

💼 Career

Understanding type inference is important for Kotlin developers to write idiomatic and efficient code in Android and backend development.

1

Create variables with inferred types

Create three variables called number, text, and flag and assign them the values 42, "Hello", and true respectively without specifying their types.

Kotlin

# Create variables number, text, and flag with values 42, "Hello", and true
# Your code here

Need a hint?

Use val to declare variables and assign values directly without specifying types.

2

Add a variable with a floating-point value

Create a variable called price and assign it the value 19.99 without specifying its type.

Kotlin

val number = 42
val text = "Hello"
val flag = true
# Create variable price with value 19.99
# Your code here

Need a hint?

Just assign 19.99 to price using val without a type.

3

Add a variable with a list of integers

Create a variable called numbers and assign it a list of integers listOf(1, 2, 3, 4, 5) without specifying its type.

Kotlin

val number = 42
val text = "Hello"
val flag = true
val price = 19.99
# Create variable numbers with listOf(1, 2, 3, 4, 5)
# Your code here

Need a hint?

Use listOf to create a list and assign it to numbers.

4

Print all variables

Print the values of number, text, flag, price, and numbers using println.

Kotlin

val number = 42
val text = "Hello"
val flag = true
val price = 19.99
val numbers = listOf(1, 2, 3, 4, 5)
# Print all variables
# Your code here

Need a hint?

Use println for each variable to show its value on the screen.